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/atomic_32.h b/arch/x86/include/asm/atomic_32.h
index 14d3f0b..ad5b9f6 100644
--- a/arch/x86/include/asm/atomic_32.h
+++ b/arch/x86/include/asm/atomic_32.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__ATOMIC_32_H
-#define ASM_X86__ATOMIC_32_H
+#ifndef _ASM_X86_ATOMIC_32_H
+#define _ASM_X86_ATOMIC_32_H
 
 #include <linux/compiler.h>
 #include <asm/processor.h>
@@ -256,4 +256,4 @@
 #define smp_mb__after_atomic_inc()	barrier()
 
 #include <asm-generic/atomic.h>
-#endif /* ASM_X86__ATOMIC_32_H */
+#endif /* _ASM_X86_ATOMIC_32_H */