configs: stm32f746-disco: Concatenate spl and u-boot binaries

This allows to concatenate spl and u-boot binaries together.
Previously, both binaries has to be flashed separately at the correct
offset (spl at offset 0 and u-boot at offset 0x8000).
With this patch, only one binary is generated (u-boot-with-spl.bin)
and has to be copied in flash at offset 0 using openocd for example
or simply copied in exported mass storage.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/include/configs/stm32f746-disco.h b/include/configs/stm32f746-disco.h
index 8ad4bb9..b93acdc 100644
--- a/include/configs/stm32f746-disco.h
+++ b/include/configs/stm32f746-disco.h
@@ -49,6 +49,7 @@
 #define CONFIG_SYS_UBOOT_START		0x080083FD
 #define CONFIG_SYS_UBOOT_BASE		(CONFIG_SYS_FLASH_BASE + \
 					 CONFIG_SYS_SPL_LEN)
+#define CONFIG_SPL_PAD_TO		0x8000
 
 /* DT blob (fdt) address */
 #define CONFIG_SYS_FDT_BASE		(CONFIG_SYS_FLASH_BASE + \