vmlinux.lds.h: remove old check for GCC 4.9

Now that GCC 5.1 is the minimally supported version of GCC, we can
effectively revert commit 85c2ce91 ("sched, vmlinux.lds: Increase
STRUCT_ALIGNMENT to 64 bytes for GCC-4.9")

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/vmlinux.lds.h

@@ -116,11 +116,7 @@
  * GCC 4.5 and later have a 32 bytes section alignment for structures.
  * Except GCC 4.9, that feels the need to align on 64 bytes.
  */
-#if __GNUC__ == 4 && __GNUC_MINOR__ == 9
-#define STRUCT_ALIGNMENT 64
-#else
 #define STRUCT_ALIGNMENT 32
-#endif
 #define STRUCT_ALIGN() . = ALIGN(STRUCT_ALIGNMENT)
 
 /*