plat/arm: allow boards to specify second DRAM Base address

The base address for second DRAM varies across different platforms.
So allow platforms to define second DRAM by moving Juno/SGM-775 specific
definition of second DRAM base address to Juno/SGM-775 board definition
respectively, SGI/RD specific definition of DRAM 2 base address to SGI
board definition.

Change-Id: I0ecd3a2bd600b6c7019c7f06f8c452952bd07cae
Signed-off-by: Suyash Pathak <suyash.pathak@arm.com>
diff --git a/include/plat/arm/board/common/board_css_def.h b/include/plat/arm/board/common/board_css_def.h
index 4637b67..b79e0d5 100644
--- a/include/plat/arm/board/common/board_css_def.h
+++ b/include/plat/arm/board/common/board_css_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -50,13 +50,6 @@
 #define PLAT_ARM_NVM_BASE		V2M_FLASH0_BASE
 #define PLAT_ARM_NVM_SIZE		(V2M_FLASH0_SIZE - V2M_FLASH_BLOCK_SIZE)
 
-/*
- * Required platform porting definitions common to all ARM CSS-based
- * development platforms
- */
-#define PLAT_ARM_DRAM2_BASE			ULL(0x880000000)
-#define PLAT_ARM_DRAM2_SIZE			ULL(0x180000000)
-
 /* UART related constants */
 #define PLAT_ARM_BOOT_UART_BASE			SOC_CSS_UART0_BASE
 #define PLAT_ARM_BOOT_UART_CLK_IN_HZ		SOC_CSS_UART0_CLK_IN_HZ