drm/msm/a7xx: Initialize a750 "software fuse"

drm/msm/a7xx: Initialize a750 "software fuse"

On all Qualcomm platforms with a7xx GPUs, qcom_scm provides a method to
initialize cx_mem. Copy this from downstream (minus BCL which we
currently don't support). On a750, this includes a new "fuse" register
which can be used by qcom_scm to fuse off certain features like
raytracing in software. The fuse is default off, and is initialized by
calling the method. Afterwards we have to read it to find out which
features were enabled.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/592042/
Signed-off-by: Rob Clark <robdclark@chromium.org>