drm/imx: parallel-display: convert to devm_drm_bridge_alloc() API

drm/imx: parallel-display: convert to devm_drm_bridge_alloc() API

This is the new API for allocating DRM bridges.

This conversion was missed during the initial conversion of all bridges to
the new API. Thus all kernels with commit 94d50c1a2ca3 ("drm/bridge:
get/put the bridge reference in drm_bridge_attach/detach()") and using this
driver now warn due to drm_bridge_attach() incrementing the refcount, which
is not initialized without using devm_drm_bridge_alloc() for allocation.

To make the conversion simple and straightforward without messing up with
the drmm_simple_encoder_alloc(), move the struct drm_bridge from struct
imx_parallel_display_encoder to struct imx_parallel_display.

Also remove the 'struct imx_parallel_display *pd' from struct
imx_parallel_display_encoder, not needed anymore.

Fixes: 94d50c1a2ca3 ("drm/bridge: get/put the bridge reference in drm_bridge_attach/detach()")
Reported-by: Ernest Van Hoecke <ernestvanhoecke@gmail.com>
Closes: https://lore.kernel.org/all/hlf4wdopapxnh4rekl5s3kvoi6egaga3lrjfbx6r223ar3txri@3ik53xw5idyh/
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Tested-by: Ernest Van Hoecke <ernest.vanhoecke@toradex.com>
Link: https://patch.msgid.link/20251014-drm-bridge-alloc-imx-ipuv3-v1-1-a1bb1dcbff50@bootlin.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>