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/page.h b/arch/x86/include/asm/page.h
index d4f1d57..e9873a2 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__PAGE_H
-#define ASM_X86__PAGE_H
+#ifndef _ASM_X86_PAGE_H
+#define _ASM_X86_PAGE_H
 
 #include <linux/const.h>
 
@@ -206,4 +206,4 @@
 #define __HAVE_ARCH_GATE_AREA 1
 
 #endif	/* __KERNEL__ */
-#endif /* ASM_X86__PAGE_H */
+#endif /* _ASM_X86_PAGE_H */