media: venus: update calculation for dpb buffers

Use dpb color format, width and height of output port
for calculating buffer size of dpb buffers.

Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
Signed-off-by: Stanimir Varbanov <stanimir.k.varbanov@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>