drm/i915/bxt: Wait for PHY1 GRC done if PHY0 was already enabled

If we skipped PHY0 initialization because it was already enabled by
BIOS, we still have to wait for the PHY1 GRC calibration as that is
done as part of the PHY0 init.

v2:
- Use the actual PHY index in the debug message in
  broxton_phy_wait_grc_done() (Ville)

CC: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461255561-1644-1-git-send-email-imre.deak@intel.com