drm/i915/cnl: Add AUX-F support

drm/i915/cnl: Add AUX-F support

On some Cannonlake SKUs we have a dedicated Aux for port F,
that is only the full split between port A and port E.

There is still no Aux E for Port E, as in previous platforms,
because port_E still means shared lanes with port A.

v2: Rebase.
v3: Add couple missed PORT_F cases on intel_dp.
v4: Rebase and fix commit message.
v5: Squash Imre's "drm/i915: Add missing AUX_F power well string"
v6: Rebase on top of display headers rework.
v7: s/IS_CANNONLAKE/IS_CNL_WITH_PORT_F (DK)
v8: Fix Aux bits for Port F (DK)
v9: Fix VBT definition of Port F (DK).
v10: Squash power well addition to this patch to avoid
     warns as pointed by DK.
v11: Clean up squashed commit message. (David)
v12: Remove unnecessary handling for older platforms (DK)
     Adding AUX_F to PG2 following other existent ones. (DK)

Cc: David Weinehall <david.weinehall@linux.intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: David Weinehall <david.weinehall@linux.intel.com>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180129232223.766-2-rodrigo.vivi@intel.com