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>

arch/x86/include/asm/parport.h

@@ -1,5 +1,5 @@
-#ifndef ASM_X86__PARPORT_H
-#define ASM_X86__PARPORT_H
+#ifndef _ASM_X86_PARPORT_H
+#define _ASM_X86_PARPORT_H
 
 static int __devinit parport_pc_find_isa_ports(int autoirq, int autodma);
 static int __devinit parport_pc_find_nonpci_ports(int autoirq, int autodma)
@@ -7,4 +7,4 @@ static int __devinit parport_pc_find_nonpci_ports(int autoirq, int autodma)
 	return parport_pc_find_isa_ports(autoirq, autodma);
 }
 
-#endif /* ASM_X86__PARPORT_H */
+#endif /* _ASM_X86_PARPORT_H */