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/ds.h b/arch/x86/include/asm/ds.h
index c3c953a..72c5a19 100644
--- a/arch/x86/include/asm/ds.h
+++ b/arch/x86/include/asm/ds.h
@@ -20,8 +20,8 @@
  * Markus Metzger <markus.t.metzger@intel.com>, 2007-2008
  */
 
-#ifndef ASM_X86__DS_H
-#define ASM_X86__DS_H
+#ifndef _ASM_X86_DS_H
+#define _ASM_X86_DS_H
 
 #ifdef CONFIG_X86_DS
 
@@ -235,4 +235,4 @@
 #define ds_init_intel(config) do {} while (0)
 
 #endif /* CONFIG_X86_DS */
-#endif /* ASM_X86__DS_H */
+#endif /* _ASM_X86_DS_H */