ASoC: atmel_ssc_dai: fix start event for I2S mode
ASoC: atmel_ssc_dai: fix start event for I2S mode

According to the I2S specification information as following:
  - WS = 0, channel 1 (left)
  - WS = 1, channel 2 (right)
So, the start event should be TF/RF falling edge.

Reported-by: Songjun Wu <bda18c9880bad5e71f28ce8b7fb5c7b3c5774d31@atmel.com>
Signed-off-by: Bo Shen <b3e6a3251704a94eee1cf08e0adc382e6cb535ee@atmel.com>
Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@kernel.org>
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs