drm/msm/dpu: Add check for pstates

stable inclusion
from stable-v4.19.287
commit c746a0b9210cebb29511f01d2becf240408327bf
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/?h=linux-4.19.y&id=c746a0b9210cebb29511f01d2becf240408327bf



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[ 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>
Reviewed-by: Zhang Qiao <zhangqiao22@huawei.com>
Reviewed-by: zheng zucheng <zhengzucheng@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>