drm/msm: remove unnecessary mmap logic for cached BOs

No one knows what this is for anymore, so just remove it.
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>
Link: https://lore.kernel.org/r/20210423190833.25319-2-jonathan@marek.caSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_gem.c

@@ -219,21 +219,12 @@ int msm_gem_mmap_obj(struct drm_gem_object *obj,
 	vma->vm_flags &= ~VM_PFNMAP;
 	vma->vm_flags |= VM_MIXEDMAP;
 
-	if (msm_obj->flags & MSM_BO_WC) {
+	if (msm_obj->flags & MSM_BO_WC)
 		vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-	} else if (msm_obj->flags & MSM_BO_UNCACHED) {
+	else if (msm_obj->flags & MSM_BO_UNCACHED)
 		vma->vm_page_prot = pgprot_noncached(vm_get_page_prot(vma->vm_flags));
-	} else {
-		/*
-		 * Shunt off cached objs to shmem file so they have their own
-		 * address_space (so unmap_mapping_range does what we want,
-		 * in particular in the case of mmap'd dmabufs)
-		 */
-		vma->vm_pgoff = 0;
-		vma_set_file(vma, obj->filp);
-
+	else
 		vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
-	}
 
 	return 0;
 }