x86: consolidate header guards

This patch is the result of an automatic script that consolidates the
format of all the headers in include/asm-x86/.

The format:

1. No leading underscore. Names with leading underscores are reserved.
2. Pathname components are separated by two underscores. So we can
   distinguish between mm_types.h and mm/types.h.
3. Everything except letters and numbers are turned into single
   underscores.

Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
diff --git a/include/asm-x86/xen/grant_table.h b/include/asm-x86/xen/grant_table.h
index 2444d45..c4baab4 100644
--- a/include/asm-x86/xen/grant_table.h
+++ b/include/asm-x86/xen/grant_table.h
@@ -1,7 +1,7 @@
-#ifndef __XEN_GRANT_TABLE_H
-#define __XEN_GRANT_TABLE_H
+#ifndef ASM_X86__XEN__GRANT_TABLE_H
+#define ASM_X86__XEN__GRANT_TABLE_H
 
 #define xen_alloc_vm_area(size)	alloc_vm_area(size)
 #define xen_free_vm_area(area)	free_vm_area(area)
 
-#endif /* __XEN_GRANT_TABLE_H */
+#endif /* ASM_X86__XEN__GRANT_TABLE_H */