ar71xx-generic: deprecate ALFA AP121, Hornet-UB, Tube2H, N2/N5

The kernel partition on these devices is too small for the
OpenWrt 19.07 kernel. It is also located after the rootfs, so
we cannot grow it further.

Therefore mark these devices as deprecated now.

docs/user/supported_devices.rst

@@ -10,13 +10,13 @@ ar71xx-generic
 
 * ALFA Network
 
-  - AP121
+  - AP121 [#deprecated]_
   - AP121F
-  - AP121U
-  - Hornet-UB
-  - Tube2H
-  - N2
-  - N5
+  - AP121U [#deprecated]_
+  - Hornet-UB [#deprecated]_
+  - Tube2H [#deprecated]_
+  - N2 [#deprecated]_
+  - N5 [#deprecated]_
 
 * Allnet
 

targets/ar71xx-generic

@@ -25,13 +25,16 @@ device('alfa-network-ap121f', 'ap121f', {
 device('alfa-network-hornet-ub', 'hornet-ub', {
 	profile = 'HORNETUB',
 	aliases = { 'alfa-network-ap121', 'alfa-network-ap121u' },
+	deprecated = true,  -- kernel partition too small with OpenWrt 19.07
 })
 
 device('alfa-network-tube2h', 'tube2h-8M', {
 	profile = 'TUBE2H8M',
+	deprecated = true,  -- kernel partition too small with OpenWrt 19.07
 })
 device('alfa-network-n2-n5', 'alfa-nx', {
 	profile = 'ALFANX',
+	deprecated = true,  -- kernel partition too small with OpenWrt 19.07
 })