board_f: Relocate fdt even if GD_FLG_SKIP_RELOC is set

In case of OF_SEPARATE (!OF_EMBED), the devicetree blob is placed
after _end, and fdt_find_separate() always returns _end. There is
a .bss section after _end and the section is cleared before relocation.

When GD_FLG_SKIP_RELOC is set, relocation is skipped, so the blob is
still in .bss section, but will be cleared. As a result, the devicetree
become invalid.

To avoid this issue, should relocate it regardless of GD_FLG_SKIP_RELOC
in reloc_fdt().

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Reviewed-by: Simon Glass <sjg@chromium.org>