V4L/DVB (9381): On the KNC1 cards the CLOCK is clamped to a maximum limit of 90MHz, eventhough

not limited in hardware, this causes instabilities at a higher clock due to
issues such as thermal, also the divider wraps around, which causes the
demodulator core to actually run at a lower frequency. This needs to be
empirically tested whether it affects other cards. If found necessary, this
parameter needs to be moved out to the config struct such that it can be made
hardware dependant.

Reducing the CLOCK from 99MHz to 90MHz improved the acquisition time taken on
the KNC1 cards and hence such a change.

Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>