Fix NULL pointer dereference

diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index 49c04829cf34..fcf7a83f0e6f 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -85,7 +85,7 @@ msm_gem_map_vma(struct msm_gem_address_space *aspace,

    vma->mapped = true;

-   if (aspace->mmu)
+   if (aspace && aspace->mmu)
        ret = aspace->mmu->funcs->map(aspace->mmu, vma->iova, sgt,
                size, prot);