drm/msm: potential error pointer dereference in init()

stable inclusion
from stable-5.10.80
commit 3424931fa39e90b9beeb309380189ff1d1b18cb5
bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3424931fa39e90b9beeb309380189ff1d1b18cb5

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

[ Upstream commit b6816441 ]

The msm_iommu_new() returns error pointers on failure so check for that
to avoid an Oops.

Fixes: ccac7ce3 ("drm/msm: Refactor address space initialization")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NAbhinav Kumar <abhinavk@codeaurora.org>
Reviewed-by: NDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20211004103806.GD25015@kiliSigned-off-by: NDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: NRob Clark <robdclark@chromium.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c

@@ -846,6 +846,10 @@ static int _dpu_kms_mmu_init(struct dpu_kms *dpu_kms)
 		return 0;
 
 	mmu = msm_iommu_new(dpu_kms->dev->dev, domain);
+	if (IS_ERR(mmu)) {
+		iommu_domain_free(domain);
+		return PTR_ERR(mmu);
+	}
 	aspace = msm_gem_address_space_create(mmu, "dpu1",
 		0x1000, 0x100000000 - 0x1000);