drm/msm/adreno: Assign msm_gpu->pdev earlier to avoid nullptrs

In the Linux kernel, the following vulnerability has been resolved: drm/msm/adreno: Assign msm_gpu->pdev earlier to avoid nullptrs There are some cases, such as the one uncovered by Commit 46d4efcccc68 ("drm/msm/a6xx: Avoid a nullptr dereference when speedbin setting fails") where msm_gpu_cleanup() : platform_set_drvdata(gpu->pdev, NULL); is called on gpu->pdev == NULL, as the GPU device has not been fully initialized yet. Turns out that there's more than just the aforementioned path that causes this to happen (e.g. the case when there's speedbin data in the catalog, but opp-supported-hw is missing in DT). Assigning msm_gpu->pdev earlier seems like the least painful solution to this, therefore do so. Patchwork: https://patchwork.freedesktop.org/patch/602742/