media: venus: core: Set initial sm8250 video-mem bandwidth value

On the sm8250 in order to get the gcc_video_axi0_clk up and running we need
to set video-mem NOC bandwidth to non-zero.

In this case the maximum bandwidth value is set to the value given in
downstream 15000000 kbps.

bod: - Did some debug around this, set the avg_bw = 0,
       retained peak_bw = 15000000
     - Made into a standalone patch
     - Added commit log and SOB

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>