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>

arch/x86/include/asm/irq_remapping.h

@@ -1,8 +1,8 @@
-#ifndef _ASM_IRQ_REMAPPING_H
-#define _ASM_IRQ_REMAPPING_H
+#ifndef _ASM_X86_IRQ_REMAPPING_H
+#define _ASM_X86_IRQ_REMAPPING_H
 
 extern int x2apic;
 
 #define IRTE_DEST(dest) ((x2apic) ? dest : dest << 8)
 
-#endif
+#endif	/* _ASM_X86_IRQ_REMAPPING_H */