sh: Kill off long-dead HD64465 cchip support.

This code has been dead for many years. The last update it received
was in 2003 in order to update it for the driver model changes, though
it had already been in disarray and unused before that point. The only
boards that ever used this chip have not had users in many years either,
so it is finally safe to just kill it off and move on with life.

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