drm/i915/dsi: fix VBT send packet port selection for dual link DSI

intel_dsi->ports contains bitmask of enabled ports and correspondingly
logic for selecting port for VBT packet sending must use port specific
bitmask when deciding appropriate port.

Fixes: 08c59dde ("drm/i915/dsi: fix VBT send packet port selection for ICL+")
Cc: stable@vger.kernel.org
Signed-off-by: Mikko Kovanen <mikko.kovanen@aavamobile.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/DBBPR09MB466592B16885D99ABBF2393A91119@DBBPR09MB4665.eurprd09.prod.outlook.com