drm/msm/a5xx: remove null pointer check on pdev

drm/msm/a5xx: remove null pointer check on pdev

The call chain on a5xx_gpu_init is such that pdev is not going to be
null, so the null check on pdev can be removed. This also cleans up
a static analysis warning where pdev is dereferenced before the null
check which cannot actually occur.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/624180/
Signed-off-by: Rob Clark <robdclark@chromium.org>