phy: cadence: Add Cadence D-PHY Rx driver

phy: cadence: Add Cadence D-PHY Rx driver

The Cadence D-PHY can be configured in Tx (DSI) mode or Rx (CSI) mode.
Both modes have a different programming sequence and share little among
them. In addition, a PHY configured in Tx mode cannot be used in Rx mode
and vice versa. For this reason, create a separate driver for the Rx
mode to make it easier to read and maintain.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/20220301111621.2992275-2-p.yadav@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>