arm: bcmbca: replace ARCH_BCM68360 symbols in Kconfig with BCM6856

As CONFIG_ARCH_BCM68360 is replaced with CONFIG_BCM6856, update the
driver Kconfig to use the new config symbol.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Philippe Reynes <philippe.reynes@softathome.com>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 667e4bd..36095cc 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -101,7 +101,7 @@
 
 config BCM63XX_HSSPI
 	bool "BCM63XX HSSPI driver"
-	depends on (ARCH_BMIPS || ARCH_BCM68360 || \
+	depends on (ARCH_BMIPS || BCM6856 || \
 		    ARCH_BCM6858 || BCM63158)
 	help
 	  Enable the BCM6328 HSSPI driver. This driver can be used to