ARM: mach-shmobile: bonito: Add dip-switch selector

devices enable/disable are controled by dip-switch on bonito board.
If bonito core board is connected to base board,
you can check the settings from FPGA.
This patch adds basic code and controls SCIFA5 settings

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>