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/signal.h b/include/asm-x86/signal.h
index 6dac493..6ee3282 100644
--- a/include/asm-x86/signal.h
+++ b/include/asm-x86/signal.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_X86_SIGNAL_H
-#define _ASM_X86_SIGNAL_H
+#ifndef ASM_X86__SIGNAL_H
+#define ASM_X86__SIGNAL_H
 
 #ifndef __ASSEMBLY__
 #include <linux/types.h>
@@ -256,4 +256,4 @@
 #endif /* __KERNEL__ */
 #endif /* __ASSEMBLY__ */
 
-#endif
+#endif /* ASM_X86__SIGNAL_H */