drm/msm/a6xx: Avoid a nullptr dereference when speedbin setting fails

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/msm/a6xx: Avoid a nullptr dereference when speedbin setting fails Calling a6xx_destroy() before adreno_gpu_init() leads to a null pointer dereference on: msm_gpu_cleanup() : platform_set_drvdata(gpu->pdev, NULL); as gpu->pdev is only assigned in: a6xx_gpu_init() |_ adreno_gpu_init |_ msm_gpu_init() Instead of relying on handwavy null checks down the cleanup chain, explicitly de-allocate the LLC data and free a6xx_gpu instead. Patchwork: https://patchwork.freedesktop.org/patch/588919/

References

• https://git.kernel.org/stable/c/247849eeb3fd88f8990ed73e33af70d5c10f9aec
• https://git.kernel.org/stable/c/a1955a6df91355fef72a3a254700acd3cc1fec0d
• https://git.kernel.org/stable/c/617e3d1680504a3f9d88e1582892c68be155498f
• https://git.kernel.org/stable/c/46d4efcccc688cbacdd70a238bedca510acaa8e4