drivers/mhu: derive doorbell base address

In order to allow the MHUv2 driver to be usable with multiple MHUv2
controllers, use the base address of the controller from the platform
information instead of the MHUV2_BASE_ADDR macro.

Change-Id: I4dbab87b929fb0568935e6c8b339ce67937f8cd1
Signed-off-by: Aditya Angadi <aditya.angadi@arm.com>
diff --git a/plat/arm/board/rde1edge/include/platform_def.h b/plat/arm/board/rde1edge/include/platform_def.h
index 2be3f88..abb3601 100644
--- a/plat/arm/board/rde1edge/include/platform_def.h
+++ b/plat/arm/board/rde1edge/include/platform_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2018-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -16,7 +16,6 @@
 #define CSS_SGI_MAX_PE_PER_CPU		U(2)
 
 #define PLAT_CSS_MHU_BASE		UL(0x45400000)
-#define PLAT_MHUV2_BASE			PLAT_CSS_MHU_BASE
 
 /* Base address of DMC-620 instances */
 #define RDE1EDGE_DMC620_BASE0		UL(0x4e000000)