Delete ARCH_BCM4908 platform Kconfig for BCM4908 SoC as it is replaced
by ARCH_BCMBCA and move its selection to ARCH_BCMBCA.
Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20220803175455.47638-8-william.zhang@broadcom.comSigned-off-by: Florian Fainelli <f.fainelli@gmail.com>