Thanks to Felipe Balbi <felipe.balbi@nokia.com> by noticing that if clk_get
to sys_clkout2_src fails, then n810_snd_device is never released.

Add also sys_clkout2_src release into error path, error code return and
release the clocks at exit.
Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>