sh: select ARCH_DISCARD_MEMBLOCK.

We don't require it outside of the __init context, so discard it.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/Kconfig

@@ -5,6 +5,7 @@ config SUPERH
 	select HAVE_IDE if HAS_IOPORT
 	select HAVE_MEMBLOCK
 	select HAVE_MEMBLOCK_NODE_MAP
+	select ARCH_DISCARD_MEMBLOCK
 	select HAVE_OPROFILE
 	select HAVE_GENERIC_DMA_COHERENT
 	select HAVE_ARCH_TRACEHOOK