Replace textual license notices with SPDX-License-Identifier lines. Add an SPDX-License-Identifier for the Makefile.
Signed-off-by: Andreas Färber
# SPDX-License-Identifier: GPL-2.0+ obj-$(CONFIG_OWL_PM_DOMAINS_HELPER) += owl-sps-helper.o obj-$(CONFIG_OWL_PM_DOMAINS) += owl-sps.o
