arch/tile/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 tile platform is unnecessary.

Remove it for cleanup.

Link: http://lkml.kernel.org/r/1504234599-29533-7-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>
Acked-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/tile/include/asm/topology.h

@@ -29,12 +29,6 @@ static inline int cpu_to_node(int cpu)
 	return cpu_2_node[cpu];
 }
 
-/*
- * Returns the number of the node containing Node 'node'.
- * This architecture is flat, so it is a pretty simple function!
- */
-#define parent_node(node) (node)
-
 /* Returns a bitmask of CPUs on Node 'node'. */
 static inline const struct cpumask *cpumask_of_node(int node)
 {