drm/msm/dpu: remove GC and IGC related code from dpu catalog

Gamma Correction (GC) and Inverse Gamma Correction(IGC) is
currently unused. In addition dpu_dspp_sub_blks didn't even have an igc
member describing the block.

Drop related code from the dpu hardware catalog otherwise this becomes a
burden to carry across chipsets in the catalog.

changes in v3:
	- drop IGC related code from dpu_hw_catalog too
	- update commit text accordingly

Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Patchwork: https://patchwork.freedesktop.org/patch/534725/
Link: https://lore.kernel.org/r/20230428223646.23595-3-quic_abhinavk@quicinc.com


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>