Add position and replication as overlay caps, and pass overlay caps as an
argument to the corresponding functions. Adding position and replication to
overlay caps seems a bit unnecessary, but it allows us to use the
corresponding functions for writeback too.

These caps will be set for all overlays, but not for writeback. This is done
so writeback can reuse dispc_ovl_setup() to the maximum.
Signed-off-by: Archit Taneja <archit@ti.com>