ASoC: rsnd: call rsnd_dai_pointer_update() from outside of lock

rsnd_soc_dai_trigger() will be called
after rsnd_dai_pointer_update() function
which is using rsnd_lock().
Thus, it should be called from outside of rsnd_lock().
Kernel will be hangup without this patch.
Special thanks to Kataoka-san

Reported-by: Ryo Kataoka <ryo.kataoka.wt@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@linaro.org>