x86: Fix ASM_X86__ header guards

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/include/asm/delay.h b/arch/x86/include/asm/delay.h
index 8a0da95..409a649 100644
--- a/arch/x86/include/asm/delay.h
+++ b/arch/x86/include/asm/delay.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__DELAY_H
-#define ASM_X86__DELAY_H
+#ifndef _ASM_X86_DELAY_H
+#define _ASM_X86_DELAY_H
 
 /*
  * Copyright (C) 1993 Linus Torvalds
@@ -28,4 +28,4 @@
 
 void use_tsc_delay(void);
 
-#endif /* ASM_X86__DELAY_H */
+#endif /* _ASM_X86_DELAY_H */