arm: Fixed the offset for the no relocation.

When the u-boot address of destination equal to  __start,
no relocation. relocation offset(r9) = 0.

Signed-off-by: Zhong Hongbo <bocui107@gmail.com>
Tested-by: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/cpu/arm926ejs/start.S b/arch/arm/cpu/arm926ejs/start.S
index 521d462..2188f7e 100644
--- a/arch/arm/cpu/arm926ejs/start.S
+++ b/arch/arm/cpu/arm926ejs/start.S
@@ -236,6 +236,7 @@
 	adr	r0, _start
 	sub	r9, r6, r0		/* r9 <- relocation offset */
 	cmp	r0, r6
+	moveq	r9, #0		/* no relocation. relocation offset(r9) = 0 */
 	beq	clear_bss		/* skip relocation */
 	mov	r1, r6			/* r1 <- scratch for copy loop */
 	ldr	r3, _bss_start_ofs