ASoC: mediatek: mt9195-mt6359: fix UNINIT problem

Coverity shows using uninitialized value monitor. When regmap_read
returns an error, monitor keeps the value left from earlier
computation. To prevent from the unexpected result in the case, assign
0 to monitor.

Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Link: https://lore.kernel.org/r/20230307040938.7484-3-trevor.wu@mediatek.com


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