arm64: dts: broadcom: bcmbca: bcm4908: add TWD block timer

BCM4908 TWD contains block with 4 timers. Add binding for it.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20221103105316.21294-1-zajec5@gmail.com


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