ath79-generic: (re)add support for ALFA Network AP121F

Gone due to
commit 45c84a1 ("ar71xx: drop target")

Note that it was wrongly marked as device class tiny in
commit 7fd7116e2a ("targets: add device-class flags") in the past,
the device has 64MB RAM and not 32MB.

Also, the device has no "led-running" assigned in DTS. The device has
three LEDs: "green:vpn", "green:lan" and "green:wlan". The first LED,
"green:vpn", has a "V" icon and was used to show the VPN connection
status in the vendor firmware. This LED will be used via the newly
added "led-boot" fallback in gluon-setup-mode. But will be unused
during normal operation due to the unassigned "led-running" in DTS.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

docs/user/supported_devices.rst

@@ -4,6 +4,10 @@ Supported Devices & Architectures
 ath79-generic
 --------------
 
+* ALFA Network
+
+  - AP121F
+
 * AVM
 
   - FRITZ!WLAN Repeater 300E [#avmflash]_

targets/ath79-generic

@@ -16,6 +16,12 @@ local ATH10K_PACKAGES_QCA9887 = {
 
 local ATH10K_PACKAGES_QCA9888 = {}
 
+-- ALFA NETWORK
+
+device('alfa-network-ap121f', 'alfa-network_ap121f', {
+	factory = false,
+})
+
 -- AVM
 
 device('avm-fritz-box-4020', 'avm_fritz4020', {