MLK-20978 imx8: Fix uninitialized variable in kernel DTB updating

When using fdt_next_node, the depth variable needs being initialized
first, otherwise we many get undefined depth.

Signed-off-by: Ye Li <ye.li@nxp.com>
(cherry picked from commit 1ae3d2d3859c5f2610c74cd192da2657e2600aff)

arch/arm/mach-imx/imx8/cpu.c

@@ -1196,7 +1196,7 @@ static void update_fdt_with_owned_resources(void *blob)
 	  */
 
 	int offset = 0, next_off;
-	int depth, next_depth;
+	int depth = 0, next_depth;
 	unsigned int rsrc_id;
 	int rc;