arm64: dts: bcmbca: update BCM4908 board dts files

Append "brcm,bcmbca" to compatible strings based on the new bcmbca
binding rule for BCM4908 family based boards.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Acked-by: Rafał Miłecki <rafal@milecki.pl>
Link: https://lore.kernel.org/r/20220803175455.47638-4-william.zhang@broadcom.com


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