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/elf.h b/arch/x86/include/asm/elf.h
index 26bc15f..40ca1be 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__ELF_H
-#define ASM_X86__ELF_H
+#ifndef _ASM_X86_ELF_H
+#define _ASM_X86_ELF_H
 
 /*
  * ELF register definitions..
@@ -333,4 +333,4 @@
 extern unsigned long arch_randomize_brk(struct mm_struct *mm);
 #define arch_randomize_brk arch_randomize_brk
 
-#endif /* ASM_X86__ELF_H */
+#endif /* _ASM_X86_ELF_H */