sh: add common dram_init() function for all boards

Generic board support assumes a different method of specifying
DRAM size on board, also it can be shared among all boards, notably
only sh7763rdp board has a custom legacy dram_init(), however
the difference is only in printing some additional information,
this feature can be removed.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile
index c5cf89f..7be20b1 100644
--- a/arch/sh/lib/Makefile
+++ b/arch/sh/lib/Makefile
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-
+obj-y	+= board.o
 obj-$(CONFIG_CMD_BOOTM) += bootm.o
 ifeq ($(CONFIG_CPU_SH2),y)
 obj-y	+= time_sh2.o