Boards with CONFIG_OF_LIBFDT enabled are not able to boot old-style
kernels using the board info structure (instead of passing a device tree)
This change allows the old style booting to be used if the fdt argument
was not passed to 'bootm'.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NKim Phillips <kim.phillips@freescale.com>