Populate the PHY ops with the downstream driver as reference.

There are a couple of TODOs which need to be resolved:
- The PHY timings are all hardcoded for now. This needs to be replaced
  with automatic calculations once we get/understand them.
- There are some lane configuration registers which use a new
  representation between physical and logical lane mappings. For now,
  we've hardcoced them to follow the default mapping (i.e
  logical 0 -> phy 0, logical 1 -> phy 1 etc).
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>