Fix the issue of _end symbol not being found while building

Fix the nand_spl build for the hawkboard

Signed-off-by: Sughosh Ganu <urwithsughosh@gmail.com>

nand_spl/board/davinci/da8xxevm/u-boot.lds

@@ -68,6 +68,8 @@ SECTIONS
 
 	__got_end = .;
 
+	_end = .;
+
 	. = ALIGN(4);
 	__bss_start = .;
 	.bss : { *(.bss) }