arm64: dts: mt7622: handle interrupts from MT7531 switch on BPI-R64

arm64: dts: mt7622: handle interrupts from MT7531 switch on BPI-R64

Since commit ba751e28d442 ("net: dsa: mt7530: add interrupt support")
the mt7530 driver can act as an interrupt controller. Wire up irq line
of the MT7531 switch on the BananaPi BPi-R64 board, so the status of
the PHYs of the five 1000Base-T ports doesn't need to be polled any
more.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Link: https://lore.kernel.org/r/ZEA-DV_OsmFg5egL@makrotopia.org
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>