arm64: bcmbca: Merge ARCH_BCM4908 to ARCH_BCMBCA

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>

arch/arm64/Kconfig.platforms

@@ -47,15 +47,6 @@ config ARCH_BCM2835
 	  This enables support for the Broadcom BCM2837 and BCM2711 SoC.
 	  These SoCs are used in the Raspberry Pi 3 and 4 devices.
 
-config ARCH_BCM4908
-	bool "Broadcom BCM4908 family"
-	select ARCH_BCMBCA
-	select GPIOLIB
-	help
-	  This enables support for the Broadcom BCM4906, BCM4908 and
-	  BCM49408 SoCs. These SoCs use Brahma-B53 cores and can be
-	  found in home routers.
-
 config ARCH_BCM_IPROC
 	bool "Broadcom iProc SoC Family"
 	select COMMON_CLK_IPROC
@@ -66,6 +57,7 @@ config ARCH_BCM_IPROC
 
 config ARCH_BCMBCA
 	bool "Broadcom Broadband Carrier Access (BCA) origin SoC"
+	select GPIOLIB
 	help
 	  Say Y if you intend to run the kernel on a Broadcom Broadband ARM-based
 	  BCA chipset.