board: stm32: remove fdt_high and fdt_highinitrd_high

For stm32 f4, f7 and h7 boards, remove fdt_high and
initrd_high as they shouldn't be used, this allows the fdt
and initrd relocation.
This implies to set CONFIG_SYS_BOOTMAPSZ to indicate the
amount of memory available to contain kernel, device tree
and initrd for relocation.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Patrick DELAUNAY <patrick.delaunay@st.com>
diff --git a/include/configs/stm32f746-disco.h b/include/configs/stm32f746-disco.h
index 6d82a9c..45343d2 100644
--- a/include/configs/stm32f746-disco.h
+++ b/include/configs/stm32f746-disco.h
@@ -7,6 +7,11 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#include <linux/sizes.h>
+
+/* For booting Linux, use the first 6MB of memory */
+#define CONFIG_SYS_BOOTMAPSZ		SZ_4M + SZ_2M
+
 #define CONFIG_SYS_FLASH_BASE		0x08000000
 #define CONFIG_SYS_INIT_SP_ADDR		0x20050000
 
@@ -52,8 +57,6 @@
 			"scriptaddr=0xC0418000\0"		\
 			"pxefile_addr_r=0xC0428000\0" \
 			"ramdisk_addr_r=0xC0438000\0"		\
-			"fdt_high=0xffffffffffffffff\0"		\
-			"initrd_high=0xffffffffffffffff\0"	\
 			BOOTENV
 
 /*