ath10k: switch to use SPDX license identifiers

Use SPDX identifiers everywhere in ath10k.

Makefile was incorrectly marked in commit b24413180f56 ("License cleanup: add
SPDX GPL-2.0 license identifier to files with no license"), fix that as well.

Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

ath10k: add testmode

Add testmode interface for starting and using UTF firmware which is used to run
factory tests. This is implemented by adding new state ATH10K_STATE_UTF and user
space can enable this state with ATH10K_TM_CMD_UTF_START command. To go back to
normal mode user space can send ATH10K_TM_CMD_UTF_STOP.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>