The cpu mask value in interrupt property inherits from bcm4908.dtsi
which sets to four cpus. Correct the value to two cpus for dual core
BCM4906 SoC.
Fixes: c8b404fb05dc ("arm64: dts: broadcom: bcm4908: add BCM4906
Netgear R8000P DTS files")
Signed-off-by: William Zhang <william.zhang@xxxxxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>