MLK-18177-2: drm/bridge: nwl-dsi: Change init sequence for panel

MLK-18177-2: drm/bridge: nwl-dsi: Change init sequence for panel

Currently, the DSI panel init sequence is made in the prepare function,
right after the reset pin is asserted. This implies that at this moment,
the DSI host needs to be enabled. If the DSI host is enabled during
panel prepare, there will be DSI signal on the DSI lanes during the
panel reset, which is wrong.

In order to fix this, the init sequence was moved from prepare to
enable, while the reset sequence is made in prepare. Also, the DSI host
intialization has to be updated in such a way that the host won't send
DSI signals on the lanes between the prepare and enable of the panel.

Signed-off-by: Robert Chiras <robert.chiras@nxp.com>