x86: canonicalize remaining header guards

Canonicalize a few remaining header guards, with the exception for
those which are still in subarchitecture directories.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/include/asm/gpio.h b/arch/x86/include/asm/gpio.h
index 1c07aad..49dbfdf 100644
--- a/arch/x86/include/asm/gpio.h
+++ b/arch/x86/include/asm/gpio.h
@@ -13,8 +13,8 @@
  * (at your option) any later version.
  */
 
-#ifndef _ASM_I386_GPIO_H
-#define _ASM_I386_GPIO_H
+#ifndef _ASM_X86_GPIO_H
+#define _ASM_X86_GPIO_H
 
 #include <asm-generic/gpio.h>