drm/tidss: fix modeset init for DPI panels

The connector type for DISPC's DPI videoport was set the LVDS instead of
DPI. This causes any DPI panel setup to fail with tidss, making all DPI
panels unusable.

Fix this by using correct connector type.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Fixes: 32a1795f

 ("drm/tidss: New driver for TI Keystone platform Display SubSystem")
Cc: stable@vger.kernel.org # v5.7+
Link: https://patchwork.freedesktop.org/patch/msgid/20200604080214.107159-1-tomi.valkeinen@ti.com
Reviewed-by: Jyri Sarha <jsarha@ti.com>