radeon_hd: Missed a % for a B_PRI
radeon_hd: Update DisplayPort aux for DCE6

* DCE6 requires a non-0 value for lpAuxRequest
  (0 is reserved)
radeon_hd: crtc_memreq only on DCE 3 - 5

* Prevent some atombios missing table errors
  on DCE 6 and later