media: venus: Enable low power setting for encoder

Set the FW to run in low power for encoder
to accommodate more session without losing much on quality.

Signed-off-by: Dikshita Agarwal <dikshita@codeaurora.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>