arm64: dts: qcom: sm8250-hdk: specify ZAP firmware name

arm64: dts: qcom: sm8250-hdk: specify ZAP firmware name

The DT file has GPU node enabled, but doesn't specify the file name of
the ZAP firmware, which means using a default file name. Specify the
name to the ZAP shader firmware, pointing to the file in the
linux-firmware repo.

Fixes: 04a3605b184e ("arm64: dts: qcom: add sm8250 GPU nodes")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20251213-zap-names-v1-2-c889af173911@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>