ARM: omap4: Provide do_wfi() for Thumb-2

For CONFIG_THUMB2_KERNEL, the existing definition of do_wfi() will
insert invalid code into the instruction stream.

Any assembler which can assemble Thumb-2 is guaranteed to accept
the "wfi" mnemonic, so for the Thumb-2 case, just use the mnemonic.

The ARM case is left as-is.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/include/mach/omap4-common.h

@@ -17,8 +17,12 @@
  * wfi used in low power code. Directly opcode is used instead
  * of instruction to avoid mulit-omap build break
  */
+#ifdef CONFIG_THUMB2_KERNEL
+#define do_wfi() __asm__ __volatile__ ("wfi" : : : "memory")
+#else
 #define do_wfi()			\
 		__asm__ __volatile__ (".word	0xe320f003" : : : "memory")
+#endif
 
 #ifdef CONFIG_CACHE_L2X0
 extern void __iomem *l2cache_base;