ARM: 7553/1: proc-v7: Ensure correct instruction set after cpu_reset

Because mov pc,<Rn> never switches instruction set when executed in
Thumb code, Thumb-2 kernels will silently execute the target code
after cpu_reset as Thumb code, even if the passed code pointer
denotes ARM (bit 0 clear).

This patch uses bx instead, ensuring the correct instruction set
for the target code.

Thumb code in the kernel is not supported prior to ARMv7, so other
CPUs are not affected.
Signed-off-by: NDave Martin <dave.martin@linaro.org>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/proc-v7.S

@@ -57,7 +57,7 @@ ENTRY(cpu_v7_reset)
  THUMB(	bic	r1, r1, #1 << 30 )		@ SCTLR.TE (Thumb exceptions)
 	mcr	p15, 0, r1, c1, c0, 0		@ disable MMU
 	isb
-	mov	pc, r0
+	bx	r0
 ENDPROC(cpu_v7_reset)
 	.popsection