atm: zatm: Fix empty body Clang warnings

Clang warns:

drivers/atm/zatm.c:513:7: error: while loop has empty body
[-Werror,-Wempty-body]
zwait;
^
drivers/atm/zatm.c:513:7: note: put the semicolon on a separate line to
silence this warning

Get rid of this warning by using an empty do-while loop. While we're at
it, add parentheses to make it clear that this is a function-like macro.

Link: https://github.com/ClangBuiltLinux/linux/issues/42
Suggested-by: Masahiro Yamada <[e-mail]>
Signed-off-by: Nathan Chancellor <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/atm/zatm.c

···
 #define zin_n(r) inl(zatm_dev->base+r*4)
 #define zin(r) inl(zatm_dev->base+uPD98401_##r*4)
 #define zout(v,r) outl(v,zatm_dev->base+uPD98401_##r*4)
-#define zwait while (zin(CMR) & uPD98401_BUSY)
+#define zwait() do {} while (zin(CMR) & uPD98401_BUSY)
 
 /* RX0, RX1, TX0, TX1 */
 static const int mbx_entries[NR_MBX] = { 1024,1024,1024,1024 };
···
 
 static void zpokel(struct zatm_dev *zatm_dev,u32 value,u32 addr)
 {
-	zwait;
+	zwait();
 	zout(value,CER);
 	zout(uPD98401_IND_ACC | uPD98401_IA_BALL |
 	    (uPD98401_IA_TGT_CM << uPD98401_IA_TGT_SHIFT) | addr,CMR);
···
 
 static u32 zpeekl(struct zatm_dev *zatm_dev,u32 addr)
 {
-	zwait;
+	zwait();
 	zout(uPD98401_IND_ACC | uPD98401_IA_BALL | uPD98401_IA_RW |
 	  (uPD98401_IA_TGT_CM << uPD98401_IA_TGT_SHIFT) | addr,CMR);
-	zwait;
+	zwait();
 	return zin(CER);
 }
 
···
 	}
 	if (first) {
 		spin_lock_irqsave(&zatm_dev->lock, flags);
-		zwait;
+		zwait();
 		zout(virt_to_bus(first),CER);
 		zout(uPD98401_ADD_BAT | (pool << uPD98401_POOL_SHIFT) | count,
 		    CMR);
···
 	}
 	if (zatm_vcc->pool < 0) return -EMSGSIZE;
 	spin_lock_irqsave(&zatm_dev->lock, flags);
-	zwait;
+	zwait();
 	zout(uPD98401_OPEN_CHAN,CMR);
-	zwait;
+	zwait();
 	DPRINTK("0x%x 0x%x\n",zin(CMR),zin(CER));
 	chan = (zin(CMR) & uPD98401_CHAN_ADDR) >> uPD98401_CHAN_ADDR_SHIFT;
 	spin_unlock_irqrestore(&zatm_dev->lock, flags);
···
 		pos = vcc->vci >> 1;
 		shift = (1-(vcc->vci & 1)) << 4;
 		zpokel(zatm_dev,zpeekl(zatm_dev,pos) & ~(0xffff << shift),pos);
-		zwait;
+		zwait();
 		zout(uPD98401_NOP,CMR);
-		zwait;
+		zwait();
 		zout(uPD98401_NOP,CMR);
 		spin_unlock_irqrestore(&zatm_dev->lock, flags);
 	}
 	spin_lock_irqsave(&zatm_dev->lock, flags);
-	zwait;
+	zwait();
 	zout(uPD98401_DEACT_CHAN | uPD98401_CHAN_RT | (zatm_vcc->rx_chan <<
 	    uPD98401_CHAN_ADDR_SHIFT),CMR);
-	zwait;
+	zwait();
 	udelay(10); /* why oh why ... ? */
 	zout(uPD98401_CLOSE_CHAN | uPD98401_CHAN_RT | (zatm_vcc->rx_chan <<
 	    uPD98401_CHAN_ADDR_SHIFT),CMR);
-	zwait;
+	zwait();
 	if (!(zin(CMR) & uPD98401_CHAN_ADDR))
 		printk(KERN_CRIT DEV_LABEL "(itf %d): can't close RX channel "
 		    "%d\n",vcc->dev->number,zatm_vcc->rx_chan);
···
 	skb_queue_tail(&zatm_vcc->tx_queue,skb);
 	DPRINTK("QRP=0x%08lx\n",zpeekl(zatm_dev,zatm_vcc->tx_chan*VC_SIZE/4+
 	  uPD98401_TXVC_QRP));
-	zwait;
+	zwait();
 	zout(uPD98401_TX_READY | (zatm_vcc->tx_chan <<
 	    uPD98401_CHAN_ADDR_SHIFT),CMR);
 	spin_unlock_irqrestore(&zatm_dev->lock, flags);
···
 	}
 	spin_lock_irqsave(&zatm_dev->lock, flags);
 #if 0
-	zwait;
+	zwait();
 	zout(uPD98401_DEACT_CHAN | (chan << uPD98401_CHAN_ADDR_SHIFT),CMR);
 #endif
-	zwait;
+	zwait();
 	zout(uPD98401_CLOSE_CHAN | (chan << uPD98401_CHAN_ADDR_SHIFT),CMR);
-	zwait;
+	zwait();
 	if (!(zin(CMR) & uPD98401_CHAN_ADDR))
 		printk(KERN_CRIT DEV_LABEL "(itf %d): can't close TX channel "
 		    "%d\n",vcc->dev->number,chan);
···
 	zatm_vcc->tx_chan = 0;
 	if (vcc->qos.txtp.traffic_class == ATM_NONE) return 0;
 	spin_lock_irqsave(&zatm_dev->lock, flags);
-	zwait;
+	zwait();
 	zout(uPD98401_OPEN_CHAN,CMR);
-	zwait;
+	zwait();
 	DPRINTK("0x%x 0x%x\n",zin(CMR),zin(CER));
 	chan = (zin(CMR) & uPD98401_CHAN_ADDR) >> uPD98401_CHAN_ADDR_SHIFT;
 	spin_unlock_irqrestore(&zatm_dev->lock, flags);
···
 	struct zatm_dev *zatm_dev;
 
 	zatm_dev = ZATM_DEV(dev);
-	zwait;
+	zwait();
 	zout(value,CER);
 	zout(uPD98401_IND_ACC | uPD98401_IA_B0 |
 	    (uPD98401_IA_TGT_PHY << uPD98401_IA_TGT_SHIFT) | addr,CMR);
···
 	struct zatm_dev *zatm_dev;
 
 	zatm_dev = ZATM_DEV(dev);
-	zwait;
+	zwait();
 	zout(uPD98401_IND_ACC | uPD98401_IA_B0 | uPD98401_IA_RW |
 	  (uPD98401_IA_TGT_PHY << uPD98401_IA_TGT_SHIFT) | addr,CMR);
-	zwait;
+	zwait();
 	return zin(CER) & 0xff;
 }