tcl/target: add SPDX tag

For historical reasons, no license information was added to the
tcl files. This makes trivial adding the SPDX tag through script:
	fgrep -rL SPDX tcl/ target| while read a;do \
	sed -i '1{i# SPDX-License-Identifier: GPL-2.0-or-later\n
	}' $a;done

With no specific license information from the author, let's extend
the OpenOCD project license GPL-2.0-or-later to the files.

Change-Id: I7b2610300b24cccd07bfa6fb5f1266970d5d3a1b
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7027
Tested-by: jenkins

tcl/target/qualcomm_qca4531.cfg

@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
 # The QCA4531 is a two stream (2x2) 802.11b/g/n single-band programmable
 # Wi-Fi System-on-Chip (SoC) for the Internet of Things (IoT).
 #