ARM: 7946/1: asm: __und_usr_thumb need byteswap instructions in BE case

__und_usr_thumb function deals with thumb2 opcodes. In case of BE
image, it needs to byteswap half word thumb2 encoded instructions
before further processing them.

Without this fix BE image user-land thread executing first VFP
instruction encoded in thumb2 fails with SIGILL, because kernel
does not recognize instruction and does not enable VFP.
Reported-by: Corey Melton <comelton@cisco.com>
Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/entry-armv.S

@@ -451,9 +451,11 @@ __und_usr_thumb:
 	.arch	armv6t2
 #endif
 2:	ldrht	r5, [r4]
+ARM_BE8(rev16	r5, r5)				@ little endian instruction
 	cmp	r5, #0xe800			@ 32bit instruction if xx != 0
 	blo	__und_usr_fault_16		@ 16bit undefined instruction
 3:	ldrht	r0, [r2]
+ARM_BE8(rev16	r0, r0)				@ little endian instruction
 	add	r2, r2, #2			@ r2 is PC + 2, make it PC + 4
 	str	r2, [sp, #S_PC]			@ it's a 2x16bit instr, update
 	orr	r0, r0, r5, lsl #16