drm/panel: jdi-lpm102a188a: Fix error code in jdi_panel_prepare()

drm/panel: jdi-lpm102a188a: Fix error code in jdi_panel_prepare()

If the mipi_dsi_dual() macro fails, the error code is stored in
dsi_ctx.accum_err.  Propagate that error back to the caller instead
of returning success as the current code does.

Fixes: a6adf47d30cc ("drm/panel: jdi-lpm102a188a: Fix bug and clean up driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/aKcRfq8xBrFmhqmO@stanley.mountain