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/irq_regs_32.h b/arch/x86/include/asm/irq_regs_32.h
index 316a3b2..af2f02d 100644
--- a/arch/x86/include/asm/irq_regs_32.h
+++ b/arch/x86/include/asm/irq_regs_32.h
@@ -4,8 +4,8 @@
  *
  * Jeremy Fitzhardinge <jeremy@goop.org>
  */
-#ifndef ASM_X86__IRQ_REGS_32_H
-#define ASM_X86__IRQ_REGS_32_H
+#ifndef _ASM_X86_IRQ_REGS_32_H
+#define _ASM_X86_IRQ_REGS_32_H
 
 #include <asm/percpu.h>
 
@@ -26,4 +26,4 @@
 	return old_regs;
 }
 
-#endif /* ASM_X86__IRQ_REGS_32_H */
+#endif /* _ASM_X86_IRQ_REGS_32_H */