m68k: replace gcc specific macros with ones from compiler.h

There is <linux/compiler.h> which provides macros for various gcc
specific constructs.  Eg: __weak for __attribute__((weak)).  I've
cleaned all instances of gcc specific attributes with the right macros
for all files under /arch/m68k

Link: http://lkml.kernel.org/r/1485540901-1988-3-git-send-email-gidisrael@gmail.com
Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/m68k/include/asm/natfeat.h

@@ -6,6 +6,7 @@
  * This software may be used and distributed according to the terms of
  * the GNU General Public License (GPL), incorporated herein by reference.
  */
+#include <linux/compiler.h>
 
 #ifndef _NATFEAT_H
 #define _NATFEAT_H
@@ -17,6 +18,6 @@ void nf_init(void);
 void nf_shutdown(void);
 
 void nfprint(const char *fmt, ...)
-	__attribute__ ((format (printf, 1, 2)));
+	__printf(1, 2);
 
 # endif /* _NATFEAT_H */