compiler-gcc4.h: Reorder macros based upon gcc ver

compiler-gcc4.h: Reorder macros based upon gcc ver

This helps to keep the file from getting confusing, removes one duplicate
version check and should encourage future editors to put new macros where
they belong.

Signed-off-by: Daniel Santos <daniel.santos@pobox.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>