ARM: shmobile: armadillo: tidyup DT node naming

According to ePAPR spec,
this patch tidies up DT node name.

This patch removed un-used "touchscreen" label

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>