drm/i915: Fix build warning on 32-bit

The gtt.stolen_size field is of type size_t, and so should be printed
using %zu to avoid build warnings on either 32-bit and 64-bit builds.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -348,7 +348,7 @@ int i915_gem_init_stolen(struct drm_device *dev)
 	 * memory, so just consider the start. */
 	reserved_total = stolen_top - reserved_base;
 
-	DRM_DEBUG_KMS("Memory reserved for graphics device: %luK, usable: %luK\n",
+	DRM_DEBUG_KMS("Memory reserved for graphics device: %zuK, usable: %luK\n",
 		      dev_priv->gtt.stolen_size >> 10,
 		      (dev_priv->gtt.stolen_size - reserved_total) >> 10);