ARM: socfpga: Add DRAM bank size initialization function

Add function for both multiple DRAM bank and single DRAM bank size
initialization. This common functionality could be used by every single
SOCFPGA board.

Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
Tested-by: Ley Foon Tan <ley.foon.tan@intel.com>

arch/arm/mach-socfpga/board.c

@@ -28,6 +28,13 @@ int board_init(void)
 	return 0;
 }
 
+int dram_init_banksize(void)
+{
+	fdtdec_setup_memory_banksize();
+
+	return 0;
+}
+
 #ifdef CONFIG_USB_GADGET
 struct dwc2_plat_otg_data socfpga_otg_data = {
 	.usb_gusbcfg	= 0x1417,