extmod/modnetwork: Consolidate definition of common drivers.

Most extmod network drivers were being defined on a per-port basis,
duplicating code and making enabling a driver on a new port harder.

This consolidates extmod driver declarations and removes the existing
per-port definitions of them.

This commit has been verified to be a no-op in terms of firmware change.

Signed-off-by: Andrew Leech <andrew.leech@planetinnovation.com.au>

extmod/network_esp_hosted.c

@@ -48,6 +48,8 @@
 #include "esp_hosted_wifi.h"
 #include "esp_hosted_hal.h"
 
+extern const mp_obj_type_t mod_network_esp_hosted_type;
+
 typedef struct _esp_hosted_obj_t {
     mp_obj_base_t base;
     uint32_t itf;