Fix "W" macro in unified.h

Please, fold into 0becb088
aka "Thumb-2: Add macros for the unified assembler syntax"

otherwise:

	crypto/cast6.c:372:39: error: macro "W" passed 2 arguments, but takes just 1
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm/include/asm/unified.h

@@ -35,7 +35,9 @@
 
 #define ARM(x...)
 #define THUMB(x...)	x
+#ifdef __ASSEMBLY__
 #define W(instr)	instr.w
+#endif
 #define BSYM(sym)	sym + 1
 
 #else	/* !CONFIG_THUMB2_KERNEL */
@@ -45,7 +47,9 @@
 
 #define ARM(x...)	x
 #define THUMB(x...)
+#ifdef __ASSEMBLY__
 #define W(instr)	instr
+#endif
 #define BSYM(sym)	sym
 
 #endif	/* CONFIG_THUMB2_KERNEL */