drm/dp: Set the connector's TILE property even for DP SST connectors

Current driver sets the tile property only for DP MST connectors.
However there are some tiled displays where each SST connector
carries a single tile. So we need to attach this property object
for every connector and set it for every connector (DP SST and MST).
Plus since the tile information is obtained as a result of EDID
parsing, the best place to update tile property is where we update
edid property.
Also now we dont need to explicitly set this now for MST connectors.

This has been tested with xrandr --props and modetest and verified
that TILE property is exposed correctly.

Cc: Dave Airlie <airlied@redhat.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190313021722.10068-1-manasi.d.navare@intel.com