mt76x0: init hw capabilities

Enable hw capabilities supported by mt76-usb layer
- fast_xmit
- tx/rx amsdu
- MFP
- non-linear tx skbs

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>