media: ccs-pll: End search if there are no better values available

The VT divisor search can be ended if we've already found the value that
corresponds exactly the total divisor, as there are no better (lower)
values available.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>