driver: brcm: add mdio driver

Change-Id: Id873670f68a4c584e3b7b586cab28565bb5a1c27
Signed-off-by: Bharat Gooty <bharat.gooty@broadcom.com>
diff --git a/plat/brcm/board/stingray/platform.mk b/plat/brcm/board/stingray/platform.mk
index c5509bb..7fcf373 100644
--- a/plat/brcm/board/stingray/platform.mk
+++ b/plat/brcm/board/stingray/platform.mk
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2019-2020, Broadcom
+# Copyright (c) 2019-2021, Broadcom
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -190,7 +190,8 @@
 				plat/${SOC_DIR}/src/tz_sec.c \
 				drivers/arm/tzc/tzc400.c \
 				plat/${SOC_DIR}/driver/plat_emmc.c \
-				plat/${SOC_DIR}/src/topology.c
+				plat/${SOC_DIR}/src/topology.c \
+				drivers/brcm/mdio/mdio.c
 
 ifeq (${USE_CHIMP},yes)
 PLAT_BL_COMMON_SOURCES	+=	drivers/brcm/chimp.c