drm/i915/icl: use combophy/TC helper functions during display detection

Instead of directly comparing HPD pins use intel_port_is_combophy/tc
helper functions to distinguish between combophy/TC ports.

Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181003072203.12848-3-mahesh1.kumar@intel.com