ASoC: codec: wm9860: avoid maybe-uninitialized warning

The new PLL configuration code triggers a harmless warning:

sound/soc/codecs/wm8960.c: In function 'wm8960_configure_clocking':
sound/soc/codecs/wm8960.c:735:3: error: 'best_freq_out' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
   wm8960_set_pll(codec, freq_in, best_freq_out);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/soc/codecs/wm8960.c:699:12: note: 'best_freq_out' was declared
here

Fix this by reworking the code such that:

1) When there is no PLL freq available return -EINVAL and make
sure *bclk_idx, *dac_idx, *sysclk_idx are initialized with
invalid values.

2) When there is a PLL freq available initialize *bclk_idx,
*dac_idx and *sysclk_idx with correct values and immediately
return the freq available.

Fixes: 84fdc00d ("ASoC: codec: wm9860: Refactor PLL out freq search")
Fixes: 303e8954 ("ASoC: codec: wm8960: Stop when a matching PLL freq is found")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>