ARM: shmobile: Force ARM mode to compile reset vector for secondary CPUs

Instructions start from boot vector must be ARM mode.
This patch specify ARM mode explicitly and use 'bx' instruction to be
able to change to Thumb mode.
Signed-off-by: NTetsuyuki Kobayashi <koba@kmckk.co.jp>
Acked-by: NMagnus Damm <damm@opensource.se>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm/mach-shmobile/headsmp.S

@@ -26,10 +26,13 @@ ENDPROC(shmobile_invalidate_start)
  * This will be mapped at address 0 by SBAR register.
  * We need _long_ jump to the physical address.
  */
+	.arm
 	.align  12
 ENTRY(shmobile_boot_vector)
 	ldr     r0, 2f
-	ldr     pc, 1f
+	ldr     r1, 1f
+	bx	r1
+
 ENDPROC(shmobile_boot_vector)
 
 	.globl	shmobile_boot_fn