fwserial: (coding style) if/else bracket matching

Style-only modifications to make checkpatch.pl --file --strict a bit happier.
if/else bracket matching (either none or both options should be bracketed).

Signed-off-by: Dominique van den Broeck <domdevlin@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>