drm/i915/display: Convert intel_bw.c internally to intel_display

Update intel_bw.c internally use intel_display. Conversion of the public
interface will come as a follow-up.

v2:
  - Prefer intel_uncore_read() for MCHBAR registers. (Ville)
v3:
  - Remove the unnecessary inclusion of intel_de.h after changes from
    v2. (Ville)

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250311-xe3lpd-bandwidth-update-v5-1-a95a9d90ad71@intel.com


Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>