powerpc/xive: Remove P9 DD1 flag XIVE_IRQ_FLAG_SHIFT_BUG

This flag was used to support the PHB4 LSIs on P9 DD1 and we have
stopped supporting this CPU when DD2 came out. See skiboot commit:

https://github.com/open-power/skiboot/commit/0b0d15e3c170

Signed-off-by: Cédric Le Goater <[e-mail]>
Reviewed-by: Greg Kurz <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/include/asm/opal-api.h

···
 	OPAL_XIVE_IRQ_TRIGGER_PAGE	= 0x00000001,
 	OPAL_XIVE_IRQ_STORE_EOI		= 0x00000002,
 	OPAL_XIVE_IRQ_LSI		= 0x00000004,
-	OPAL_XIVE_IRQ_SHIFT_BUG		= 0x00000008,
+	OPAL_XIVE_IRQ_SHIFT_BUG		= 0x00000008, /* P9 DD1.0 workaround */
 	OPAL_XIVE_IRQ_MASK_VIA_FW	= 0x00000010,
 	OPAL_XIVE_IRQ_EOI_VIA_FW	= 0x00000020,
 };

arch/powerpc/include/asm/xive.h

···
 };
 #define XIVE_IRQ_FLAG_STORE_EOI	0x01
 #define XIVE_IRQ_FLAG_LSI	0x02
-#define XIVE_IRQ_FLAG_SHIFT_BUG	0x04
+/* #define XIVE_IRQ_FLAG_SHIFT_BUG	0x04 */ /* P9 DD1.0 workaround */
 #define XIVE_IRQ_FLAG_MASK_FW	0x08
 #define XIVE_IRQ_FLAG_EOI_FW	0x10
 #define XIVE_IRQ_FLAG_H_INT_ESB	0x20

arch/powerpc/kvm/book3s_xive_native.c

···
 	 * ordering.
 	 */
 
-	if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
-		offset |= offset << 4;
-
 	val = in_be64(xd->eoi_mmio + offset);
 	return (u8)val;
 }

arch/powerpc/kvm/book3s_xive_template.c

···
 	if (offset == XIVE_ESB_SET_PQ_10 && xd->flags & XIVE_IRQ_FLAG_STORE_EOI)
 		offset |= XIVE_ESB_LD_ST_MO;
 
-	if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
-		offset |= offset << 4;
-
 	val =__x_readq(__x_eoi_page(xd) + offset);
 #ifdef __LITTLE_ENDIAN__
 	val >>= 64-8;

arch/powerpc/sysdev/xive/common.c

···
 	if (offset == XIVE_ESB_SET_PQ_10 && xd->flags & XIVE_IRQ_FLAG_STORE_EOI)
 		offset |= XIVE_ESB_LD_ST_MO;
 
-	/* Handle HW errata */
-	if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
-		offset |= offset << 4;
-
 	if ((xd->flags & XIVE_IRQ_FLAG_H_INT_ESB) && xive_ops->esb_rw)
 		val = xive_ops->esb_rw(xd->hw_irq, offset, 0, 0);
 	else
···
 
 static void xive_esb_write(struct xive_irq_data *xd, u32 offset, u64 data)
 {
-	/* Handle HW errata */
-	if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
-		offset |= offset << 4;
-
 	if ((xd->flags & XIVE_IRQ_FLAG_H_INT_ESB) && xive_ops->esb_rw)
 		xive_ops->esb_rw(xd->hw_irq, offset, data, 1);
 	else
···
 } xive_irq_flags[] = {
 	{ XIVE_IRQ_FLAG_STORE_EOI, "STORE_EOI" },
 	{ XIVE_IRQ_FLAG_LSI,       "LSI"       },
-	{ XIVE_IRQ_FLAG_SHIFT_BUG, "SHIFT_BUG" },
 	{ XIVE_IRQ_FLAG_MASK_FW,   "MASK_FW"   },
 	{ XIVE_IRQ_FLAG_EOI_FW,    "EOI_FW"    },
 	{ XIVE_IRQ_FLAG_H_INT_ESB, "H_INT_ESB" },

arch/powerpc/sysdev/xive/native.c

···
 		data->flags |= XIVE_IRQ_FLAG_STORE_EOI;
 	if (opal_flags & OPAL_XIVE_IRQ_LSI)
 		data->flags |= XIVE_IRQ_FLAG_LSI;
-	if (opal_flags & OPAL_XIVE_IRQ_SHIFT_BUG)
-		data->flags |= XIVE_IRQ_FLAG_SHIFT_BUG;
 	if (opal_flags & OPAL_XIVE_IRQ_MASK_VIA_FW)
 		data->flags |= XIVE_IRQ_FLAG_MASK_FW;
 	if (opal_flags & OPAL_XIVE_IRQ_EOI_VIA_FW)