ARM: shmobile: marzen: enable CONFIG_DEVTMPFS in defconfig

This reverts commit 41307133
("ARM: shmobile: marzen: Do not enable CONFIG_DEVTMPFS defconfig").

DEVTMPFS is needed for udev.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
[horms+renesas@verge.net.au: Added subject of reverted patch to changelog]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>