Benjamin Valentin 840be824d4 gnrc_netif: relax 6lo MTU assertion for 802.15.4g
802.15.4g devices have a 2047 byte PDU.
So the assertion `netif->ipv6.mtu == IPV6_MIN_MTU` is too strict here.

This is only enforced on init, so changing the modulation at run-time
did not catch this bug.

To test, use e.g. `at86rf215` with

    CFLAGS += -DAT86RF215_DEFAULT_PHY_MODE=IEEE802154_PHY_MR_OQPSK

fixes #14164
2020-05-29 15:59:23 +02:00
..