ASoC: codecs: tx-macro: fix active_decimator array

ASoC: codecs: tx-macro: fix active_decimator array

currently active_decimator[] is unsigned long however we store negative
values when there is no decimator setup -1.

This is first bug, and the second bug is that we do not check if the decimator
is valid before writing to register using decimator as offset in
CDC_TXn_TX_PATH_CTL()

Fix these both by making active_decimator as integer array and adding check
in tx_macro_digital_mute() before accessing CDC_TXn_TX_PATH_CTL() register.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220906170112.1984-5-srinivas.kandagatla@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>