treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

samples: Introduce Qualcomm QMI sample client

Introduce a sample driver that register for server notifications and
spawn clients for each available test service (service 15). The spawned
clients implements the interface for encoding "ping" and "data" requests
and decode the responses from the remote.

Acked-By: Chris Lew <clew@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>