drm/i915: Allow DSI dual link to be configured on any pipe

drm/i915: Allow DSI dual link to be configured on any pipe

commit 824257857fd81f5e749831ff9cd63566b5a86abe upstream.

Just like single link MIPI panels, similarly for dual link panels, pipe
to be configured is based on the DVO port from VBT Block 2. In hardware,
Port A is mapped with Pipe A and Port C is mapped with Pipe B.

This issue got introduced in -

commit 7e9804fdcffc650515c60f524b8b2076ee59e710
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Fri Jan 16 14:27:23 2015 +0200

    drm/i915/dsi: add drm mipi dsi host support

Signed-off-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>