powerpc/64s: Fix conversion of slb_miss_common to use RFI_TO_USER/KERNEL

The back port of commit c7305645 ("powerpc/64s: Convert
slb_miss_common to use RFI_TO_USER/KERNEL") missed a hunk needed to
restore cr6.

Fixes: 48cc95d4 ("powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/powerpc/kernel/exceptions-64s.S

@@ -680,6 +680,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
 .machine	push
 .machine	"power4"
 	mtcrf	0x80,r9
+	mtcrf	0x02,r9		/* I/D indication is in cr6 */
 	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
 .machine	pop