arm64: dts: qcom: sdm632-fairphone-fp3: Enable display and GPU

arm64: dts: qcom: sdm632-fairphone-fp3: Enable display and GPU

Add the description for the display panel found on this phone.
Unfortunately the LCDB module on PMI632 isn't yet supported upstream so
we need to use a dummy regulator-fixed in the meantime.

And with this done we can also enable the GPU and set the zap shader
firmware path.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
Link: https://lore.kernel.org/r/20250611-fp3-display-v4-4-ef67701e7687@lucaweiss.eu
Signed-off-by: Bjorn Andersson <andersson@kernel.org>