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>
diff --git a/arch/x86/include/asm/mach-default/apm.h b/arch/x86/include/asm/mach-default/apm.h
index fc392ec..20370c6 100644
--- a/arch/x86/include/asm/mach-default/apm.h
+++ b/arch/x86/include/asm/mach-default/apm.h
@@ -3,8 +3,8 @@
  *  Split out from apm.c by Osamu Tomita <tomita@cinet.co.jp>
  */
 
-#ifndef _ASM_X86_MACH_DEFAULT__APM_H
-#define _ASM_X86_MACH_DEFAULT__APM_H
+#ifndef _ASM_X86_MACH_DEFAULT_APM_H
+#define _ASM_X86_MACH_DEFAULT_APM_H
 
 #ifdef APM_ZERO_SEGS
 #	define APM_DO_ZERO_SEGS \
@@ -70,4 +70,4 @@
 	return error;
 }
 
-#endif /* _ASM_X86_MACH_DEFAULT__APM_H */
+#endif /* _ASM_X86_MACH_DEFAULT_APM_H */