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/boot.h b/include/asm-x86/boot.h
index 2faed7e..825de5d 100644
--- a/include/asm-x86/boot.h
+++ b/include/asm-x86/boot.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_BOOT_H
-#define _ASM_BOOT_H
+#ifndef ASM_X86__BOOT_H
+#define ASM_X86__BOOT_H
 
 /* Don't touch these, unless you really know what you're doing. */
 #define DEF_INITSEG	0x9000
@@ -25,4 +25,4 @@
 #define BOOT_STACK_SIZE	0x1000
 #endif
 
-#endif /* _ASM_BOOT_H */
+#endif /* ASM_X86__BOOT_H */