mt76x0: merge mt76x0_dev in mt76x02_dev

Merge mt76x0_dev data structure in mt76x02_dev one and remove
duplicated code. Remove unused definition in mt76x0.h.
Moreover merge mt76x0_caldata and mt76x02_rx_freq_cal data structures.
This is a preliminary patch for rxwi unification.

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