drm/bridge: Move legacy bridge driver out of imx directory for multi-platform use

drm/bridge: Move legacy bridge driver out of imx directory for multi-platform use

As suggested by Dmitry, the DRM legacy bridge driver can be pulled
out of imx/ subdir for multi-platform use. The driver is also renamed
to make it more generic and suitable for platforms other than i.MX.

Signed-off-by: Damon Ding <damon.ding@rock-chips.com>
Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Heiko Stuebner <heiko@sntech.de> # rk3588
Link: https://patch.msgid.link/20260409065301.446670-3-damon.ding@rock-chips.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>