drm/i915/display: use intel_encoder_is/to_* functions

drm/i915/display: use intel_encoder_is/to_* functions

Wherever possible, replace the port/phy based functions with the encoder
based functions:

intel_is_c10phy()	-> intel_encoder_is_c10phy()
intel_phy_is_combo()	-> intel_encoder_is_combo()
intel_phy_is_tc()	-> intel_encoder_is_tc()
intel_port_to_phy()	-> intel_encoder_to_phy()
intel_port_to_tc()	-> intel_encoder_to_tc()

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ce8d116fcdd7662fa0a0817200a8e6fda313e496.1710949619.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>