drm/msm: Fix IS_ERR_OR_NULL() vs NULL check in a5xx_submit_in_rb()

drm/msm: Fix IS_ERR_OR_NULL() vs NULL check in a5xx_submit_in_rb()

BugLink: https://bugs.launchpad.net/bugs/2037005
[ Upstream commit 6e8a996563ecbe68e49c49abd4aaeef69f11f2dc ]

The msm_gem_get_vaddr() returns an ERR_PTR() on failure, and a null
is catastrophic here, so we should use IS_ERR_OR_NULL() to check
the return value.

Fixes: 6a8bd08d0465 ("drm/msm: add sudo flag to submit ioctl")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/547712/
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>