x86: consolidate header guards

This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.

The format:

1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
   distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
   underscores.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
diff --git a/include/asm-x86/asm.h b/include/asm-x86/asm.h
index 9722032..2439ae4 100644
--- a/include/asm-x86/asm.h
+++ b/include/asm-x86/asm.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_X86_ASM_H
-#define _ASM_X86_ASM_H
+#ifndef ASM_X86__ASM_H
+#define ASM_X86__ASM_H
 
 #ifdef __ASSEMBLY__
 # define __ASM_FORM(x)	x
@@ -39,4 +39,4 @@
 	_ASM_PTR #from "," #to "\n" \
 	" .previous\n"
 
-#endif /* _ASM_X86_ASM_H */
+#endif /* ASM_X86__ASM_H */