ARM: dts: bcmbca: bcm6846: fix timer node cpu mask flag

The cpu mask flag value should match the number of cpu cores in the
chip. Correct the value to two cpus for BCM6846 dual core SoC.

Fixes: de1a99ac ("ARM: dts: Add DTS files for bcmbca SoC BCM6846")
Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20220801194647.29437-1-william.zhang@broadcom.com


Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>