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

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/[email protected]
Signed-off-by: Dou Liyang <[email protected]>
Reported-by: Michael Ellerman <[email protected]>
Acked-by: Chris Metcalf <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>