media: ov6650: Don't reapply pixel clock divisor on format change

As calculation of pixel clock hardware divisor no longer depends on
mbus format specific maximum pixel clock, there is no need to reapply
the divisor on format change.  Drop related code from ov6650_s_fmt()
helper.

Since a master clock hardware divisor, so far applied only together
with the pixel clock divisor in a single operation, will no longer be
applied from ov6650_s_fmt(), apply it, still using a hardcoded value
for now, from  ov6650_prog_dflt() helper so hardware is still
initialised correctly on device probe.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>