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/topology.h b/arch/x86/include/asm/topology.h
index 7eca9bc..90ac771 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -22,8 +22,8 @@
  *
  * Send feedback to <colpatch@us.ibm.com>
  */
-#ifndef ASM_X86__TOPOLOGY_H
-#define ASM_X86__TOPOLOGY_H
+#ifndef _ASM_X86_TOPOLOGY_H
+#define _ASM_X86_TOPOLOGY_H
 
 #ifdef CONFIG_X86_32
 # ifdef CONFIG_X86_HT
@@ -255,4 +255,4 @@
 }
 #endif
 
-#endif /* ASM_X86__TOPOLOGY_H */
+#endif /* _ASM_X86_TOPOLOGY_H */