ASoC: davinci-mcasp: Clear TXSTAT register before activating serializers

Follow the guideline from the TRM:
Before starting, clear the respective transmitter and receiver status
registers

To avoid stale state stored in the status registers.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/davinci/davinci-mcasp.c

@@ -192,6 +192,7 @@ static void mcasp_start_rx(struct davinci_mcasp *mcasp)
 	}
 
 	/* Activate serializer(s) */
+	mcasp_set_reg(mcasp, DAVINCI_MCASP_RXSTAT_REG, 0xFFFFFFFF);
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLR_REG, RXSERCLR);
 	/* Release RX state machine */
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLR_REG, RXSMRST);
@@ -220,6 +221,7 @@ static void mcasp_start_tx(struct davinci_mcasp *mcasp)
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXHCLKRST);
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXCLKRST);
 	/* Activate serializer(s) */
+	mcasp_set_reg(mcasp, DAVINCI_MCASP_TXSTAT_REG, 0xFFFFFFFF);
 	mcasp_set_ctl_reg(mcasp, DAVINCI_MCASP_GBLCTLX_REG, TXSERCLR);
 
 	/* wait for XDATA to be cleared */