sh: Add support for AP-SH4AD-0A board.

This adds preliminary support for the alpha project AP-SH4AD-0A reference
platform (SH7786 based).

Additional platform information available at:

	http://www.apnet.co.jp/product/superh/ap-sh4ad-0a.html



Signed-off-by: Paul Mundt <lethal@linux-sh.org>