ASoC: simple-card: fix simple_dai clk lookup

The clock needs to be stored in the simple_dai structure, so it can
be enabled later on. This has been broken during the conversion to use
devm_* functions for the clk lookup.

Fixes: e984fd61 (ASoC: simple-card: use devm_get_clk_from_child())
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>