ARM: dts: bcmbca: bcm63178: 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 three cpus for BCM63178 triple core SoC.

Fixes: fc85b7e6 ("ARM: dts: add dts files for bcmbca soc 63178")
Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20220801194448.29363-1-william.zhang@broadcom.com


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