ASoC: Intel: boards: sof-wm8804: add check for PLL setting

Currently the return from snd_soc_dai_set_pll is not checking for
failure, this is the only driver in the kernel that ignores this,
so it probably should be added for sake of completeness.  Fix this
by adding an error return check.

Addresses-Coverity: ("Unchecked return value")
Fixes: f139546f ("ASoC: Intel: boards: sof-wm8804: support for Hifiberry Digiplus boards")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210226185653.1071321-1-colin.king@canonical.com


Signed-off-by: Mark Brown <broonie@kernel.org>