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/reboot.h b/include/asm-x86/reboot.h
index 206f355..1c2f0ce 100644
--- a/include/asm-x86/reboot.h
+++ b/include/asm-x86/reboot.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_REBOOT_H
-#define _ASM_REBOOT_H
+#ifndef ASM_X86__REBOOT_H
+#define ASM_X86__REBOOT_H
 
 struct pt_regs;
 
@@ -18,4 +18,4 @@
 void native_machine_shutdown(void);
 void machine_real_restart(const unsigned char *code, int length);
 
-#endif	/* _ASM_REBOOT_H */
+#endif /* ASM_X86__REBOOT_H */