drm/msm/dpu: Set PINGPONG block length to zero for DPU >= 7.0.0

drm/msm/dpu: Set PINGPONG block length to zero for DPU >= 7.0.0

Despite downstream DTS stating otherwise, the PINGPONG block has no
registers starting with DPU revision 7.0.0.  TEAR registers are gone
since DPU 5.0.0 after being moved to the INTF block, and DSC registers
are gone since 7.0.0, leaving only the dither sub-block.

A future patch, part of the DSC 1.2 series, should disable DSC functions
on the PINGPONG block for all DPU >= 7.0.0 hardware.

Fixes: 4a352c2fc15a ("drm/msm/dpu: Introduce SC8280XP")
Fixes: 0e91bcbb0016 ("drm/msm/dpu: Add SM8350 to hw catalog")
Fixes: 100d7ef6995d ("drm/msm/dpu: add support for SM8450")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/534206/
Link: https://lore.kernel.org/r/20230411-dpu-intf-te-v4-7-27ce1a5ab5c6@somainline.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>