sh: fix up the ubc clock definition for sh7785.

Presently the SH7785 code misdefines the UBC clock connection ID in
relation to the other CPUs. This makes it uniform, so that things like
single-stepping work again.

Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>