drm/msm: Switch to pfn mappings

I'm not entirely sure why we were using VM_MIXEDMAP.  These are never
CoW mappings.  Let's switch to be more consistent with what other
drivers and the GEM shmem helpers do.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/491218/
Link: https://lore.kernel.org/r/20220625225454.81039-2-robdclark@gmail.com

drivers/gpu/drm/msm/msm_gem.c

@@ -259,7 +259,8 @@ static vm_fault_t msm_gem_fault(struct vm_fault *vmf)
 	VERB("Inserting %p pfn %lx, pa %lx", (void *)vmf->address,
 			pfn, pfn << PAGE_SHIFT);
 
-	ret = vmf_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
+	ret = vmf_insert_pfn(vma, vmf->address, pfn);
+
 out_unlock:
 	msm_gem_unlock(obj);
 out:
@@ -1051,7 +1052,7 @@ static int msm_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
-	vma->vm_flags |= VM_IO | VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTDUMP;
+	vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
 	vma->vm_page_prot = msm_gem_pgprot(msm_obj, vm_get_page_prot(vma->vm_flags));
 
 	return 0;