drm/msm/dpu: Add check for pstates

stable inclusion
from stable-v5.10.173
commit e9743b3052e125c44b555f07f2876a4bdccfd983
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I7F2UT
CVE: CVE-2023-3220

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e9743b3052e125c44b555f07f2876a4bdccfd983



--------------------------------

[ Upstream commit 93340e10 ]

As kzalloc may fail and return NULL pointer,
it should be better to check pstates
in order to avoid the NULL pointer dereference.

Fixes: 25fdd593 ("drm/msm: Add SDM845 DPU support")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/514160/
Link: https://lore.kernel.org/r/20221206080236.43687-1-jiasheng@iscas.ac.cn


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Xia Fukun <xiafukun@huawei.com>