move definition of macros likely and unlikely to compiler.h

the macros likely and unlikely were defined in include/linux/mtd/compat.h,
but used in code not related to MTD. moved the macro definitions to compiler.h

Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
diff --git a/include/compiler.h b/include/compiler.h
index e602cce..332618e 100644
--- a/include/compiler.h
+++ b/include/compiler.h
@@ -125,4 +125,7 @@
 /* compiler options */
 #define uninitialized_var(x)		x = x
 
+#define likely(x)	__builtin_expect(!!(x), 1)
+#define unlikely(x)	__builtin_expect(!!(x), 0)
+
 #endif