ARM: at91: lds: use "_image_binary_end" for DT location

The MMC SPL locates the BSS section to a different memory region
from text, then use "_image_binary_end" variable to point to the
correct device tree location.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>

arch/arm/mach-at91/armv7/u-boot-spl.lds

@@ -47,6 +47,8 @@ SECTIONS
 		*(.__end)
 	} >.sram
 
+	_image_binary_end = .;
+
 	.bss :
 	{
 		. = ALIGN(4);