drm/imx: move imx_drm_connector_destroy to imx-tve

drm/imx: move imx_drm_connector_destroy to imx-tve

The imx-tve driver is the only remaining user of
imx_drm_connector_destroy(). Move the function to imx-tve.c

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Chris Healy <cphealy@gmail.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de> # on imx6q-nitrogen6x
Link: https://patchwork.freedesktop.org/patch/msgid/20240602-drm-imx-cleanup-v3-12-e549e2a43100@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>