cmd: fdt: Fix fdt address information after the movement

This patch fixes the address information of fdt.

wrong case:
 => fdt addr 0x48000000
 => fdt move 0x48000000 0x41000000 0xa000
 => fdt addr
The address of the fdt is 48000000

Active address in this case is 0x41000000.

Signed-off-by: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>