drm/rockchip: dsi: Disable PLL clock on bind error

Fix some error handling here noticed in review of other changes.

Fixes: 2d4f7bda

 ("drm/rockchip: dsi: migrate to use dw-mipi-dsi bridge driver")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Reported-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210928143413.v3.4.I8bb7a91ecc411d56bc155763faa15f289d7fc074@changeid