drm/xe: Don't use absolute path in generated header comment

drm/xe: Don't use absolute path in generated header comment

Building the XE driver through Yocto throws this QA warning:

    WARNING: mc:house:linux-stable-6.17-r0 do_package_qa: QA Issue: File /usr/src/debug/linux-stable/6.17/drivers/gpu/drm/xe/generated/xe_device_wa_oob.h in package linux-stable-src contains reference to TMPDIR [buildpaths]
    WARNING: mc:house:linux-stable-6.17-r0 do_package_qa: QA Issue: File /usr/src/debug/linux-stable/6.17/drivers/gpu/drm/xe/generated/xe_wa_oob.h in package linux-stable-src contains reference to TMPDIR [buildpaths]

...because the comment at the top of the generated header contains the
absolute path to the rules file at build time:

    * This file was generated from rules: /home/calvinow/git/meta-house/build/tmp-house/work-shared/nuc14rvhu7/kernel-source/drivers/gpu/drm/xe/xe_device_wa_oob.rules

Fix this minor annoyance by putting the basename of the rules file in
the generated comment instead of the absolute path, so the generated
header contents no longer depend on the location of the kernel source.

Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Link: https://patch.msgid.link/20251222165441.516102-2-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>