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/msgbuf.h b/include/asm-x86/msgbuf.h
index 7e4e948..1b538c9 100644
--- a/include/asm-x86/msgbuf.h
+++ b/include/asm-x86/msgbuf.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_X86_MSGBUF_H
-#define _ASM_X86_MSGBUF_H
+#ifndef ASM_X86__MSGBUF_H
+#define ASM_X86__MSGBUF_H
 
 /*
  * The msqid64_ds structure for i386 architecture.
@@ -36,4 +36,4 @@
 	unsigned long  __unused5;
 };
 
-#endif /* _ASM_X86_MSGBUF_H */
+#endif /* ASM_X86__MSGBUF_H */