Set intr1 to 0 in mt7996_irq_tasklet() in order to avoid possible
uninitialized variable usage if wed is not active for hif2.

Fixes: 83eafc92 ("wifi: mt76: mt7996: add wed tx support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>