mt76x0: phy: set antenna parameter according to wireless band

Move mt76x0_ant_select routine in __mt76x0_phy_set_channel in order to
configure antenna parameters according to the current wireless channel

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