x32: Check __ILP32__ instead of __LP64__ for x32

Check __LP64__ isn't a reliable way to tell if we are compiling for x32
since __LP64__ isnn't specified by x86-64 psABI.  Not all x86-64
compilers define __LP64__, which was added to GCC 3.3. The updated x32
psABI:

https://sites.google.com/site/x32abi/documents

definse _ILP32 and __ILP32__ for x32.  GCC trunk and 4.7 branch have
been updated to define _ILP32 and __ILP32__ for x32.  This patch
replaces __LP64__ check with __ILP32__.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/include/asm/unistd.h b/arch/x86/include/asm/unistd.h
index 37cdc9d..4437001 100644
--- a/arch/x86/include/asm/unistd.h
+++ b/arch/x86/include/asm/unistd.h
@@ -63,10 +63,10 @@
 #else
 # ifdef __i386__
 #  include <asm/unistd_32.h>
-# elif defined(__LP64__)
-#  include <asm/unistd_64.h>
-# else
+# elif defined(__ILP32__)
 #  include <asm/unistd_x32.h>
+# else
+#  include <asm/unistd_64.h>
 # endif
 #endif