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/sembuf.h b/arch/x86/include/asm/sembuf.h
index 81f06b7..ee50c80 100644
--- a/arch/x86/include/asm/sembuf.h
+++ b/arch/x86/include/asm/sembuf.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__SEMBUF_H
-#define ASM_X86__SEMBUF_H
+#ifndef _ASM_X86_SEMBUF_H
+#define _ASM_X86_SEMBUF_H
 
 /*
  * The semid64_ds structure for x86 architecture.
@@ -21,4 +21,4 @@
 	unsigned long	__unused4;
 };
 
-#endif /* ASM_X86__SEMBUF_H */
+#endif /* _ASM_X86_SEMBUF_H */