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/bitops.h b/arch/x86/include/asm/bitops.h
index 451a747..3600103 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__BITOPS_H
-#define ASM_X86__BITOPS_H
+#ifndef _ASM_X86_BITOPS_H
+#define _ASM_X86_BITOPS_H
 
 /*
  * Copyright 1992, Linus Torvalds.
@@ -448,4 +448,4 @@
 #include <asm-generic/bitops/minix.h>
 
 #endif /* __KERNEL__ */
-#endif /* ASM_X86__BITOPS_H */
+#endif /* _ASM_X86_BITOPS_H */