drm/panel: visionox-rm69299: don't unregister DSI device

[ Upstream commit 9e4d3f4f ]

The DSI device for the panel was registered by the DSI host, so it is an
error to unregister it from the panel driver. Drop the call to
mipi_dsi_device_unregister().

Fixes: c7f66d32

 ("drm/panel: add support for rm69299 visionox panel")
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240404-drop-panel-unregister-v1-1-9f56953c5fb9@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>