clk: clk-twl6040: Free of_provider at remove

use devm variant for of_provider registration so provider is freed
at exit.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>