Nokia RX-51: Do not clear unknown memory in lowlevel_init.S

If kernel image in uImage or zImage format is not detected by
lowlevel_init.S code then do not clear memory location where image was
expected. If image is not detected then this memory region is unknown.
So do not unconditionally clear it.

Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/board/nokia/rx51/lowlevel_init.S b/board/nokia/rx51/lowlevel_init.S
index 53697fd..1cf8f8d 100644
--- a/board/nokia/rx51/lowlevel_init.S
+++ b/board/nokia/rx51/lowlevel_init.S
@@ -76,7 +76,7 @@
 	ldr	r4, [r0, #36]	/* r4 - 4 bytes header of kernel at offset 36 */
 	ldr	r5, z_magic	/* r5 - LINUX_ARM_ZIMAGE_MAGIC */
 	cmp	r4, r5
-	bne	copy_kernel_end	/* skip if invalid image */
+	bne	skip_copy	/* skip if invalid image */
 
 copy_kernel_loop:
 	ldmdb	r1!, {r3 - r10}
@@ -84,12 +84,12 @@
 	cmp	r1, r0
 	bhi	copy_kernel_loop
 
-copy_kernel_end:
-
 	/* remove header in source kernel image */
 	mov	r5, #0
 	str	r5, [r0]	/* remove 4 bytes header of kernel uImage */
 	str	r5, [r0, #36]	/* remove 4 bytes header of kernel zImage */
 
+skip_copy:
+
 	/* Returns */
 	b	save_boot_params_ret