arm: restore fdt_fixup_ethernet call to do_bootm_linux

Commit 0a672d49 "arm: Add Prep subcommand support to bootm" re-organized
do_bootm_linux for ARM. During the re-organization, the call to
fdt_fixup_ethernet() was removed. I assume this was useful, so add it
back.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Tom Rini <trini@ti.com>

arch/arm/lib/bootm.c

@@ -256,6 +256,7 @@ static int create_fdt(bootm_headers_t *images)
 
 	fdt_chosen(*of_flat_tree, 1);
 	fixup_memory_node(*of_flat_tree);
+	fdt_fixup_ethernet(*of_flat_tree);
 	fdt_initrd(*of_flat_tree, *initrd_start, *initrd_end, 1);
 
 	return 0;