drm: meson: Remove unneeded semicolon

Fixes coccicheck warning:

drivers/gpu/drm/meson/meson_crtc.c:360:3-4: Unneeded semicolon
drivers/gpu/drm/meson/meson_plane.c:181:2-3: Unneeded semicolon

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1576468701-69717-1-git-send-email-zhengbin13@huawei.com