Documentation: devres: add a missing section for networking helpers

Add a new section for networking devres helpers to devres.rst and list
the two existing devm functions.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/driver-api/driver-model/devres.rst

@@ -372,6 +372,10 @@ MUX
   devm_mux_chip_register()
   devm_mux_control_get()
 
+NET
+  devm_alloc_etherdev()
+  devm_alloc_etherdev_mqs()
+
 PER-CPU MEM
   devm_alloc_percpu()
   devm_free_percpu()