drm/mediatek: dp: Remove extra semicolon

Remove unnecessary semicolon at the end of switch block closing brace.
Issue identified using semicolon Coccinelle semantic patch.

Signed-off-by: Deepak R Varma <drv@mailo.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/Y8LNIt97qxLk8e70@ubun2204.myguest.virtualbox.org/


Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>