drm/amd/display: Skip DIG Check if Link is Virtual for Display Count
[WHY]
Without a check for virtual links, every link's DIG was getting
checked for enabled or disabled. If link was virtual, since it
did not have a DIG, this would cause issues.
[HOW]
Skip DIG Enable check if link is virtual and add virtual link to
to display count.
Signed-off-by: Sung Lee <sung.lee@amd.com> Reviewed-by: Yongqiang Sun <yongqiang.sun@amd.com> Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>