[SPARC64]: In sunsu driver, make sure to fully init chip for kbd/ms

We were forgetting to call sunsu_change_speed().  The reason
that replugging in the mouse cable "fixes things" is that
causes a BREAK interrupt which in turn caused a call to
sunsu_change_speed() which would get the chip setup properly.

Signed-off-by: David S. Miller <davem@davemloft.net>