regulator: core: Rely on regulator_dev_release to free constraints

As we now free the constraints in regulator_dev_release we will still
call free on the constraints pointer even if we went down an error
path in regulator_register, because it is only allocated after the
device_register. As such we no longer need to free rdev->constraints
on the error paths, so this patch removes said frees.

Fixes: 29f5f486 ("regulator: core: Move more deallocation into class unregister")
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>