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/thread_info.h b/arch/x86/include/asm/thread_info.h
index 3f4e52b..e44d379 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -4,8 +4,8 @@
  * - Incorporating suggestions made by Linus Torvalds and Dave Miller
  */
 
-#ifndef ASM_X86__THREAD_INFO_H
-#define ASM_X86__THREAD_INFO_H
+#ifndef _ASM_X86_THREAD_INFO_H
+#define _ASM_X86_THREAD_INFO_H
 
 #include <linux/compiler.h>
 #include <asm/page.h>
@@ -261,4 +261,4 @@
 extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
 #define arch_task_cache_init arch_task_cache_init
 #endif
-#endif /* ASM_X86__THREAD_INFO_H */
+#endif /* _ASM_X86_THREAD_INFO_H */