powerpc/8xx: Move tail of alignment exception out of line

When we enable VMAP_STACK there will not be enough room for the
alignment handler at 0x600 in head_8xx.S. For now move the tail of the
alignment handler out of line, and branch to it.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/head_8xx.S

@@ -145,7 +145,7 @@ Alignment:
 	li	r6, RPN_PATTERN
 	mtspr	SPRN_DAR, r6	/* Tag DAR, to be used in DTLB Error */
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	EXC_XFER_STD(0x600, alignment_exception)
+	b	.Lalignment_exception_ool
 
 /* Program check exception */
 	EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD)
@@ -153,6 +153,11 @@ Alignment:
 /* Decrementer */
 	EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE)
 
+	/* With VMAP_STACK there's not enough room for this at 0x600 */
+	. = 0xa00
+.Lalignment_exception_ool:
+	EXC_XFER_STD(0x600, alignment_exception)
+
 /* System call */
 	. = 0xc00
 SystemCall: