drm: bridge: adv7511: Add check for mipi_dsi_driver_register

As mipi_dsi_driver_register could return error if fails,
it should be better to check the return value and return error
if fails.
Moreover, if i2c_add_driver fails,  mipi_dsi_driver_register
should be reverted.

Fixes: 1e4d58cd ("drm/bridge: adv7533: Create a MIPI DSI device")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220602103401.2980938-1-jiasheng@iscas.ac.cn