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/termios.h b/arch/x86/include/asm/termios.h
index e235db2..f729563 100644
--- a/arch/x86/include/asm/termios.h
+++ b/arch/x86/include/asm/termios.h
@@ -1,5 +1,5 @@
-#ifndef ASM_X86__TERMIOS_H
-#define ASM_X86__TERMIOS_H
+#ifndef _ASM_X86_TERMIOS_H
+#define _ASM_X86_TERMIOS_H
 
 #include <asm/termbits.h>
 #include <asm/ioctls.h>
@@ -110,4 +110,4 @@
 
 #endif	/* __KERNEL__ */
 
-#endif /* ASM_X86__TERMIOS_H */
+#endif /* _ASM_X86_TERMIOS_H */