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/hpet.h b/include/asm-x86/hpet.h
index 82f1ac6..cbbbb6d 100644
--- a/include/asm-x86/hpet.h
+++ b/include/asm-x86/hpet.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86_HPET_H
-#define ASM_X86_HPET_H
+#ifndef ASM_X86__HPET_H
+#define ASM_X86__HPET_H
 
 #ifdef CONFIG_HPET_TIMER
 
@@ -90,4 +90,4 @@
 #define hpet_readl(a) 0
 
 #endif
-#endif /* ASM_X86_HPET_H */
+#endif /* ASM_X86__HPET_H */