Add the description for the display panel found on this phone.
Unfortunately the LCDB module on PM6150L 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@linaro.org>
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Link: https://lore.kernel.org/r/20240216-fp4-panel-v3-4-a556e4b79640@fairphone.comSigned-off-by: Bjorn Andersson <andersson@kernel.org>