drm/panel: novatek-nt35950: Only unregister DSI1 if it exists

drm/panel: novatek-nt35950: Only unregister DSI1 if it exists

[ Upstream commit a50be876f4fe2349dc8b056a49d87f69c944570f ]

Commit 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
introduced logic to unregister DSI1 on any sort of probe failure, as
that's not done automatically by kernel APIs.

It did not however account for cases where only one DSI host is used.
Fix that.

Fixes: 5dd45b66742a ("drm/panel: novatek-nt35950: Improve error handling")
Reported-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230417-topic-maple_panel_fixup-v1-1-07c8db606f5e@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>