ARM: shmobile: add R-Car M1A Bock-W platform support

Add basic Bock-W board support

More devices will be added on top of this patch after
PICNTRL and clock framework are in better shape.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>