ARM: 7065/1: kexec: ensure new kernel is entered in ARM state

Commit 540b5738 ("ARM: 6999/1: head, zImage: Always Enter the kernel in
ARM state") mandates that the kernel should be entered in ARM state.

If a Thumb-2 kernel kexecs a new kernel image, we need to ensure that
we change state when branching to the new code. This patch replaces a
mov pc, lr with a bx lr on Thumb-2 kernels so that we transition to ARM
state if need be.
Reviewed-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/relocate_kernel.S

@@ -57,7 +57,8 @@ relocate_new_kernel:
 	mov r0,#0
 	ldr r1,kexec_mach_type
 	ldr r2,kexec_boot_atags
-	mov pc,lr
+ ARM(	mov pc, lr	)
+ THUMB(	bx lr		)
 
 	.align