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>

drivers/net/wireless/marvell/Kconfig

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config WLAN_VENDOR_MARVELL
 	bool "Marvell devices"
 	default y

drivers/net/wireless/marvell/Makefile

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_LIBERTAS)		+= libertas/
 
 obj-$(CONFIG_LIBERTAS_THINFIRM)	+= libertas_tf/

drivers/net/wireless/marvell/libertas/Kconfig

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config LIBERTAS
 	tristate "Marvell 8xxx Libertas WLAN driver support"
 	depends on CFG80211

drivers/net/wireless/marvell/libertas_tf/Kconfig

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config LIBERTAS_THINFIRM
 	tristate "Marvell 8xxx Libertas WLAN driver support with thin firmware"
 	depends on MAC80211

drivers/net/wireless/marvell/libertas_tf/Makefile

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 libertas_tf-objs := main.o cmd.o
 
 libertas_tf_usb-objs += if_usb.o

drivers/net/wireless/marvell/mwifiex/Kconfig

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config MWIFIEX
 	tristate "Marvell WiFi-Ex Driver"
 	depends on CFG80211