media: venus: pm_helpers: use opp-table for the frequency

Some platforms (such as qcs615 and sc7180) use the same core but have
different frequency tables. Using the opp-table allows us to separate
the core description from the frequency data and supports the use of
fallback compatibles.

Reviewed-by: Vikash Garodia <quic_vgarodia@quicinc.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Renjiang Han <quic_renjiang@quicinc.com>
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>