esp_netif_ppp: Add NETIF_PPP_AUTHTYPE_NONE to esp_netif_auth_type_t
esp_netif_ppp: Add NETIF_PPP_AUTHTYPE_NONE to esp_netif_auth_type_t

To allow setting auth_type to PPPAUTHTYPE_NONE, add NETIF_PPP_AUTHTYPE_NONE
to esp_netif_auth_type_t.
So even PAP/CHAP are enabled in lwIP, the application still can set
auth_type to PPPAUTHTYPE_NONE.

Signed-off-by: Axel Lin <b6ffd6973e972cb999e8e535ab74da7fee0c035f@gmail.com>

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf