x86: drop double underscores from header guards

Drop double underscores from header guards in arch/x86/include.  They
are used inconsistently, and are not necessary.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/include/asm/visws/piix4.h

@@ -1,5 +1,5 @@
-#ifndef _ASM_X86_VISWS__PIIX4_H
-#define _ASM_X86_VISWS__PIIX4_H
+#ifndef _ASM_X86_VISWS_PIIX4_H
+#define _ASM_X86_VISWS_PIIX4_H
 
 /*
  * PIIX4 as used on SGI Visual Workstations
@@ -104,4 +104,4 @@
  */
 #define	PIIX_GPI_STPCLK		0x4	// STPCLK signal routed back in
 
-#endif /* _ASM_X86_VISWS__PIIX4_H */
+#endif /* _ASM_X86_VISWS_PIIX4_H */