dmaengine: ti: k3-psil-j721e: Add entry for CSI2RX

The CSI2RX subsystem uses PSI-L DMA to transfer frames to memory. It can
have up to 32 threads but the current driver only supports using one. So
add an entry for that one thread.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>