sh: remove extraneous ; on scif_sercon_putc wait loop

It seems we have gained an extraneous trailing ';' on one of the
wait loops in scif_sercon_putc().  Although this is completely
benign as the apparent payload is also the empty statement, it
invites error in the future.  Clean it up now.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>