powerpc: Fix multicast problem in fs_enet driver

mac-fec.c was setting individual UDP address registers instead of multicast
group address registers when joining a multicast group.
This prevented from correctly receiving UDP multicast packets.
According to datasheet, replaced hash_table_high and hash_table_low
with grp_hash_table_high and grp_hash_table_low respectively.
Also renamed hash_table_* with grp_hash_table_* in struct fec declaration
for 8xx: these registers are used only for multicast there.

Tested on a MPC5121 based board.
Build tested also against mpc866_ads_defconfig.

Signed-off-by: Andrea Galbusera <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

arch/powerpc/include/asm/8xx_immap.h

···
 	uint	fec_addr_low;		/* lower 32 bits of station address	*/
 	ushort	fec_addr_high;		/* upper 16 bits of station address	*/
 	ushort	res1;			/* reserved				*/
-	uint	fec_hash_table_high;	/* upper 32-bits of hash table		*/
-	uint	fec_hash_table_low;	/* lower 32-bits of hash table		*/
+	uint	fec_grp_hash_table_high;	/* upper 32-bits of hash table		*/
+	uint	fec_grp_hash_table_low;	/* lower 32-bits of hash table		*/
 	uint	fec_r_des_start;	/* beginning of Rx descriptor ring	*/
 	uint	fec_x_des_start;	/* beginning of Tx descriptor ring	*/
 	uint	fec_r_buff_size;	/* Rx buffer size			*/

drivers/net/fs_enet/mac-fec.c

···
 	}
 
 	FC(fecp, r_cntrl, FEC_RCNTRL_PROM);
-	FW(fecp, hash_table_high, fep->fec.hthi);
-	FW(fecp, hash_table_low, fep->fec.htlo);
+	FW(fecp, grp_hash_table_high, fep->fec.hthi);
+	FW(fecp, grp_hash_table_low, fep->fec.htlo);
 }
 
 static void set_multicast_list(struct net_device *dev)
···
 	/*
 	 * Reset all multicast.
 	 */
-	FW(fecp, hash_table_high, fep->fec.hthi);
-	FW(fecp, hash_table_low, fep->fec.htlo);
+	FW(fecp, grp_hash_table_high, fep->fec.hthi);
+	FW(fecp, grp_hash_table_low, fep->fec.htlo);
 
 	/*
 	 * Set maximum receive buffer size.