arm64: dts: renesas: eagle: specify EtherAVB PHY IRQ

Specify  EtherAVB PHY IRQ  in the Eagle board's device tree, now that we
have the GPIO support (previously phylib had to resort to polling).

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>