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/mach_ipi.h b/arch/x86/include/asm/mach-default/mach_ipi.h
index 377dfd8..fabca01 100644
--- a/arch/x86/include/asm/mach-default/mach_ipi.h
+++ b/arch/x86/include/asm/mach-default/mach_ipi.h
@@ -1,5 +1,5 @@
-#ifndef _ASM_X86_MACH_DEFAULT__MACH_IPI_H
-#define _ASM_X86_MACH_DEFAULT__MACH_IPI_H
+#ifndef _ASM_X86_MACH_DEFAULT_MACH_IPI_H
+#define _ASM_X86_MACH_DEFAULT_MACH_IPI_H
 
 /* Avoid include hell */
 #define NMI_VECTOR 0x02
@@ -61,4 +61,4 @@
 }
 #endif
 
-#endif /* _ASM_X86_MACH_DEFAULT__MACH_IPI_H */
+#endif /* _ASM_X86_MACH_DEFAULT_MACH_IPI_H */