board_f: sandbox: Move sandbox_early_getopt_check() into misc_init_f()

board_f: sandbox: Move sandbox_early_getopt_check() into misc_init_f()

We don't need a special hook for sandbox as one of the later ones will do
just as well. We can print error messages about bad options after we
print the banner. In fact, it seems better.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>