drm/i915: Use "%zu" to format size_t

Switch to %zu for printing size_t which will
fix compilation warning for 32-bit build.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221230183500.20553-1-nirmoy.das@intel.com

drivers/gpu/drm/i915/gem/i915_gem_shmem.c

@@ -238,7 +238,7 @@ static int shmem_get_pages(struct drm_i915_gem_object *obj)
 			goto rebuild_st;
 		} else {
 			dev_warn(i915->drm.dev,
-				 "Failed to DMA remap %lu pages\n",
+				 "Failed to DMA remap %zu pages\n",
 				 obj->base.size >> PAGE_SHIFT);
 			goto err_pages;
 		}