drm/i915: Fix 'mixing different enum types' warnings in intel_display_power.c

Fix the following sparse warnings:

drivers/gpu/drm/i915/display/intel_display_power.c:2431:34: warning: mixing different enum types:
drivers/gpu/drm/i915/display/intel_display_power.c:2431:34:    unsigned int enum intel_display_power_domain
drivers/gpu/drm/i915/display/intel_display_power.c:2431:34:    int enum port
drivers/gpu/drm/i915/display/intel_display_power.c:2442:37: warning: mixing different enum types:
drivers/gpu/drm/i915/display/intel_display_power.c:2442:37:    unsigned int enum intel_display_power_domain
drivers/gpu/drm/i915/display/intel_display_power.c:2442:37:    int enum port
drivers/gpu/drm/i915/display/intel_display_power.c:2468:43: warning: mixing different enum types:
drivers/gpu/drm/i915/display/intel_display_power.c:2468:43:    unsigned int enum intel_display_power_domain
drivers/gpu/drm/i915/display/intel_display_power.c:2468:43:    unsigned int enum aux_ch
drivers/gpu/drm/i915/display/intel_display_power.c:2479:35: warning: mixing different enum types:
drivers/gpu/drm/i915/display/intel_display_power.c:2479:35:    unsigned int enum intel_display_power_domain
drivers/gpu/drm/i915/display/intel_display_power.c:2479:35:    unsigned int enum aux_ch

Fixes: 979e1b32

 ("drm/i915: Sanitize the port -> DDI/AUX power domain mapping for each platform")
Reported-by: Jani Nikula <jani.nikula@intel.com>
Cc: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220510114957.406070-1-imre.deak@intel.com
(cherry picked from commit 7ecc3cc8

)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>