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/kdebug.h b/arch/x86/include/asm/kdebug.h
index fbbab66..fa7c0b9 100644
--- a/arch/x86/include/asm/kdebug.h
+++ b/arch/x86/include/asm/kdebug.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__KDEBUG_H
-#define ASM_X86__KDEBUG_H
+#ifndef _ASM_X86_KDEBUG_H
+#define _ASM_X86_KDEBUG_H
 
 #include <linux/notifier.h>
 
@@ -34,4 +34,4 @@
 extern unsigned long oops_begin(void);
 extern void oops_end(unsigned long, struct pt_regs *, int signr);
 
-#endif /* ASM_X86__KDEBUG_H */
+#endif /* _ASM_X86_KDEBUG_H */