drm/xe: Fix definition of intel_wakeref_t

drm/xe: Fix definition of intel_wakeref_t

i915 defines it as unsigned long so Xe should do the same to avoid
compilation warnings:

  CC [M]  drivers/gpu/drm/i915/i915_gem.o
  CC [M]  drivers/gpu/drm/xe/i915-display/intel_display_power_well.o
In file included from ./include/drm/drm_mm.h:51,
                 from drivers/gpu/drm/xe/xe_bo_types.h:11,
                 from drivers/gpu/drm/xe/xe_bo.h:11,
                 from ./drivers/gpu/drm/xe/compat-i915-headers/gem/i915_gem_object.h:11,
                 from ./drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h:15,
                 from drivers/gpu/drm/i915/display/intel_display_power.c:8:
drivers/gpu/drm/i915/display/intel_display_power.c: In function ‘print_async_put_domains_state’:
drivers/gpu/drm/i915/display/intel_display_power.c:408:29: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘int’ [-Wformat=]
  408 |         drm_dbg(&i915->drm, "async_put_wakeref %lu\n",
      |                             ^~~~~~~~~~~~~~~~~~~~~~~~~
  409 |                 power_domains->async_put_wakeref);
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                              |
      |                              int
./include/drm/drm_print.h:410:39: note: in definition of macro ‘drm_dev_dbg’
  410 |         __drm_dev_dbg(NULL, dev, cat, fmt, ##__VA_ARGS__)
      |                                       ^~~
./include/drm/drm_print.h:510:33: note: in expansion of macro ‘drm_dbg_driver’
  510 | #define drm_dbg(drm, fmt, ...)  drm_dbg_driver(drm, fmt, ##__VA_ARGS__)
      |                                 ^~~~~~~~~~~~~~
drivers/gpu/drm/i915/display/intel_display_power.c:408:9: note: in expansion of macro ‘drm_dbg’
  408 |         drm_dbg(&i915->drm, "async_put_wakeref %lu\n",
      |         ^~~~~~~
drivers/gpu/drm/i915/display/intel_display_power.c:408:50: note: format string is defined here
  408 |         drm_dbg(&i915->drm, "async_put_wakeref %lu\n",
      |                                                ~~^
      |                                                  |
      |                                                  long unsigned int
      |                                                %u
  CC [M]  drivers/gpu/drm/i915/i915_gem_evict.o
  CC [M]  drivers/gpu/drm/i915/i915_gem_gtt.o
  CC [M]  drivers/gpu/drm/xe/i915-display/intel_display_trace.o
  CC [M]  drivers/gpu/drm/xe/i915-display/intel_display_wa.o
  CC [M]  drivers/gpu/drm/i915/i915_query.o

Fixes: 44e694958b95 ("drm/xe/display: Implement display support")
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
(cherry picked from commit fdbadf504375886a0320ac6f84c850322a6b32e1)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>