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_32.h b/arch/x86/include/asm/page_32.h
index bdf5dba..bcde0d7 100644
--- a/arch/x86/include/asm/page_32.h
+++ b/arch/x86/include/asm/page_32.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__PAGE_32_H
-#define ASM_X86__PAGE_32_H
+#ifndef _ASM_X86_PAGE_32_H
+#define _ASM_X86_PAGE_32_H
 
 /*
  * This handles the memory map.
@@ -133,4 +133,4 @@
 #endif	/* CONFIG_X86_3DNOW */
 #endif	/* !__ASSEMBLY__ */
 
-#endif /* ASM_X86__PAGE_32_H */
+#endif /* _ASM_X86_PAGE_32_H */