dma: ti: k3-udma: Do not touch RT registers before channel configuration

dma: ti: k3-udma: Do not touch RT registers before channel configuration

Upcoming sysfw (2019.03) will not open the channelized firewalls during
init, it only going to do so in response to the channel configuration
message.

Remove the channel state checks done before the channel configuration and
move it after the configuration for warning purposes.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>