mt76: mt7615: free pci_vector if mt7615_pci_probe fails

Always free pci irq vector if mt7615_pci_probe routine fails
Moreover free irq in mt7615_pci_remove routine

Co-developed-by: Soul Huang <sean.wang@mediatek.com>
Signed-off-by: Soul Huang <sean.wang@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>