drm/i915/rkl: Handle HTI

drm/i915/rkl: Handle HTI

If HTI (also sometimes called HDPORT) is enabled at startup, it may be
using some of the PHYs and DPLLs making them unavailable for general
usage.  Let's read out the HDPORT_STATE register and avoid making use of
resources that HTI is already using.

v2:
 - Fix minor checkpatch warnings

v3:
 - Just readout HDPORT_STATE register once during init and then parse it
   later as needed.
 - Add a 'has_hti' device info flag to track whether we should readout
   HDPORT_STATE or not.  We can skip the platform/flag tests later since
   the hti_state in dev_priv will remain 0 for platforms it does not
   apply to.
 - Move PLL masking into icl_get_combo_phy_dpll() since at the moment
   RKL is the only platform that has HTI.  (Jose)

Bspec: 49189
Bspec: 53707
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200716220551.2730644-5-matthew.d.roper@intel.com
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>