x86_64: uml: fix rename header guard

In unistd_64.h, the guard macro _ASM_X86_64_UNISTD_H_ is renamed to
ASM_X86__UNISTD_64_H.

This change should be applied to arch/um/sys-x86_64/syscall_table.c.
Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/um/sys-x86_64/syscall_table.c

@@ -41,12 +41,12 @@
 #define stub_rt_sigreturn sys_rt_sigreturn
 
 #define __SYSCALL(nr, sym) extern asmlinkage void sym(void) ;
-#undef _ASM_X86_64_UNISTD_H_
+#undef ASM_X86__UNISTD_64_H
 #include <asm-x86/unistd_64.h>
 
 #undef __SYSCALL
 #define __SYSCALL(nr, sym) [ nr ] = sym,
-#undef _ASM_X86_64_UNISTD_H_
+#undef ASM_X86__UNISTD_64_H
 
 typedef void (*sys_call_ptr_t)(void);