media: qcom: iris: use new firmware name for SM8250

media: qcom: iris: use new firmware name for SM8250

The linux-firmware is providing the vpuNN_pM.mbn firmware for SM8250
since August of 2024. Stop using the legacy firmware name
(vpu-1.0/venus.mbn) and switch to the standard firmware name schema
(vpu/vpu20_p4.mbn).

Reviewed-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
Reviewed-by: Dikshita Agarwal <dikshita.agarwal@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>