colibri_imx7: prime get_ram_size() using imx_ddr_size()

Rather than passing a hardcoded maxsize to the generic get_ram_size()
function use the i.MX 7 specific imx_ddr_size() function, which extracts
the memory size at runtime by reading the DDR controller registers.

This is a purely cosmetic change as the generic get_ram_size() function
already took care of properly automatically detecting 256MB, 512MB or 1GB
modules.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Acked-by: Stefan Agner <stefan.agner@toradex.com>
diff --git a/board/toradex/colibri_imx7/colibri_imx7.c b/board/toradex/colibri_imx7/colibri_imx7.c
index 2b7591e..a4c9962 100644
--- a/board/toradex/colibri_imx7/colibri_imx7.c
+++ b/board/toradex/colibri_imx7/colibri_imx7.c
@@ -52,7 +52,7 @@
 
 int dram_init(void)
 {
-	gd->ram_size = get_ram_size((void *)PHYS_SDRAM, PHYS_SDRAM_SIZE);
+	gd->ram_size = get_ram_size((void *)PHYS_SDRAM, imx_ddr_size());
 
 	return 0;
 }
diff --git a/include/configs/colibri_imx7.h b/include/configs/colibri_imx7.h
index ff6bd67..02849ba 100644
--- a/include/configs/colibri_imx7.h
+++ b/include/configs/colibri_imx7.h
@@ -14,7 +14,6 @@
 #include "mx7_common.h"
 
 /*#define CONFIG_DBG_MONITOR*/
-#define PHYS_SDRAM_SIZE			SZ_1G
 
 /* Size of malloc() pool */
 #define CONFIG_SYS_MALLOC_LEN		(32 * SZ_1M)