media: venus: core: correct firmware name for sm8250

Firmware name for venus should be qcom/vpu-1.0/venus.mdt, not
qcom/sm8250/venus.mdt.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>