arch/sh/include/asm/topology.h: remove unused parent_node() macro

Commit a7be6e5a7f8d ("mm: drop useless local parameters of
__register_one_node()") removed the last user of parent_node().

The parent_node() macro in SUPERH platform is unnecessary.

Remove it for cleanup.

Link: http://lkml.kernel.org/r/1504234599-29533-5-git-send-email-douly.fnst@cn.fujitsu.com
Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/sh/include/asm/topology.h

@@ -5,7 +5,6 @@
 #ifdef CONFIG_NUMA
 
 #define cpu_to_node(cpu)	((void)(cpu),0)
-#define parent_node(node)	((void)(node),0)
 
 #define cpumask_of_node(node)	((void)node, cpu_online_mask)