drm/amdgpu: amdgpu_vram_mgr_new(): Clamp lpfn to total vram

The drm_mm allocator tolerated being passed end > mm->size, but the
drm_buddy allocator does not.

Restore the pre-buddy-allocator behavior of allowing such placements.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3448
Signed-off-by: John Olender <john.olender@gmail.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Author: John Olender

drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c

@@ -463,7 +463,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
 	int r;
 
 	lpfn = (u64)place->lpfn << PAGE_SHIFT;
-	if (!lpfn)
+	if (!lpfn || lpfn > man->size)
 		lpfn = man->size;
 
 	fpfn = (u64)place->fpfn << PAGE_SHIFT;