arm: bcmbca: replace ARCH_BCM6858 symbols in Kconfig with BCM6858

As CONFIG_ARCH_BCM6858 is replaced with CONFIG_BCM6858, 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 36095cc..34b92ce 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -101,8 +101,7 @@
 
 config BCM63XX_HSSPI
 	bool "BCM63XX HSSPI driver"
-	depends on (ARCH_BMIPS || BCM6856 || \
-		    ARCH_BCM6858 || BCM63158)
+	depends on (ARCH_BMIPS || BCM6856 || BCM6858 || BCM63158)
 	help
 	  Enable the BCM6328 HSSPI driver. This driver can be used to
 	  access the SPI NOR flash on platforms embedding this Broadcom