PowerPC: mpc85xx: Update ft_verify_fdt

With the changes to fdt_get_base_address() we need to modify the logic
in ft_verify_fdt() for how we check the validity of the CCSR address.

Tested-on: qemu-ppce500 -M mpc8544ds
Fixes: 336a4487 ("fdt: Correct fdt_get_base_address()")
Cc: York Sun <york.sun@nxp.com>
Cc: Wolfgang Denk <wd@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>