dmaengine: ti: k3-udma-glue: move psi-l pairing in channel en/dis functions

The NAVSS UDMA will stuck if target IP module is disabled by PM while PSI-L
threads are paired UDMA<->IP and no further transfers is possible. This
could be the case for IPs J721E Main CPSW (cpsw9g).

Hence, to avoid such situation do PSI-L threads pairing only when UDMA
channel is going to be enabled as at this time DMA consumer module expected
to be active already.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Link: https://lore.kernel.org/r/20201030203000.4281-1-grygorii.strashko@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>