Unintentional(?) GPL2 SPDX tags on i915 files

Similar to drm/amd#2053 (closed) a number of files under drivers/gpu/drm/i915 appear to have unintentional SPDX-License-Identifier: GPL-2.0 tags after b2441318.

I proposed a patch to update the two files that I came across in FreeBSD: https://lore.kernel.org/intel-gfx/CAPyFy2Aj4kKB7=dG+V32GCvGF1d+ekcyx5zamxjbr6rwLs24jQ@mail.gmail.com/T/#m82b9907d3f803bbd892ee5a592bdd2632b7da30c

Opening this issue to track this for drm/i915 in general