arm: bcmbca: replace ARCH_BCM6753 symbols in Kconfig with BCM6855

As CONFIG_ARCH_BCM6753 is replaced with CONFIG_BCM6855, 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/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index f8445e0..d6e3eeb 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -97,7 +97,7 @@
 
 config NAND_BRCMNAND_6753
 	bool "Support Broadcom NAND controller on bcm6753"
-	depends on NAND_BRCMNAND && ARCH_BCM6753
+	depends on NAND_BRCMNAND && BCM6855
 	help
 	  Enable support for broadcom nand driver on bcm6753.