drm: Wrap direct calls to driver->gem_free_object from CMA

drm: Wrap direct calls to driver->gem_free_object from CMA

Since the introduction of (struct_mutex) lockless GEM bo freeing, there
are a pair of driver vfuncs for freeing the GEM bo, of which the driver
may choose to only implement driver->gem_object_free_unlocked (and so
avoid taking the struct_mutex along the free path). However, the CMA GEM
helpers were still calling driver->gem_free_object directly, now NULL,
and promptly dying on the fancy new lockless drivers. Oops.

Robert Foss bisected this to b82caafcf2303 (drm/vc4: Use lockless gem BO
free callback) on his vc4 device, but that just serves as an enabler for
9f0ba539d13ae (drm/gem: support BO freeing without dev->struct_mutex).

Reported-by: Robert Foss <[email protected]>
Fixes: 9f0ba539d13ae (drm/gem: support BO freeing without dev->struct_mutex)
Signed-off-by: Chris Wilson <[email protected]>
Cc: Robert Foss <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Eric Anholt <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: Lucas Stach <[email protected]>
Cc: [email protected]
Reviewed-by: Daniel Vetter <[email protected]>
Tested-by: Robert Foss <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>