drm/msm/dpu: invalid parameter check in dpu_setup_dspp_pcc

In the Linux kernel, the following vulnerability has been resolved: drm/msm/dpu: invalid parameter check in dpu_setup_dspp_pcc The function performs a check on the "ctx" input parameter, however, it is used before the check. Initialize the "base" variable after the sanity check to avoid a possible NULL pointer dereference. Addresses-Coverity-ID: 1493866 ("Null pointer dereference")