compiler-gcc.h: Added new macro for gcc attribute

Added __mode(x) into compiler-gcc.h as part of a cleanup task I've taken up, to replace gcc specific attributes with macros.

Last accepted patch I sent into linux-next for crypto: d8c34b949d8c:
crypto: Replaced gcc specific attributes with macros from compiler.h

The last commit of this task that went through you: 52f5684c8e1ec
kernel: use macros from compiler.h instead of __attribute__((...))

The next patch is for cleaning up the m68k subsystem and it requires a new macro to wrap __attribute__ ((mode (...)))

---
 include/linux/compiler-gcc.h | 1 +
 1 file changed, 1 insertion(+)

index 0444b13..f1b1cfe 100644
@@ -121,6 +121,7 @@
 #define __attribute_const__	__attribute__((__const__))
 #define __maybe_unused		__attribute__((unused))
 #define __always_unused		__attribute__((unused))
+#define __mode                  __attribute__((mode(x)))
 
 /* gcc version specific checks */
 

2.7.4