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/rwsem.h b/arch/x86/include/asm/rwsem.h
index 3ff3015..ca7517d 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -29,8 +29,8 @@
  * front, then they'll all be woken up, but no other readers will be.
  */
 
-#ifndef ASM_X86__RWSEM_H
-#define ASM_X86__RWSEM_H
+#ifndef _ASM_X86_RWSEM_H
+#define _ASM_X86_RWSEM_H
 
 #ifndef _LINUX_RWSEM_H
 #error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
@@ -262,4 +262,4 @@
 }
 
 #endif /* __KERNEL__ */
-#endif /* ASM_X86__RWSEM_H */
+#endif /* _ASM_X86_RWSEM_H */