This adds preliminary support for the SH7786 CPU subtype.

While this is a dual-core CPU, only UP is supported for now. L2 cache
support is likewise not yet implemented.

More information on this particular CPU subtype is available at:

	http://www.renesas.com/fmwk.jsp?cnt=sh7786_root.jsp&fp=/products/mpumcu/superh_family/sh7780_series/sh7786_group/Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>