wifi: mt76: mt7603: fix mixed declarations and code

Move the qid variable declaration further up

Fixes: b473c0e4 ("wifi: mt76: mt7603: fix tx queue of loopback packets")
Link: https://patch.msgid.link/20240827093011.18621-1-nbd@nbd.name


Signed-off-by: Felix Fietkau <nbd@nbd.name>