tty: serial: jsm: add blank line after declarations

This patch fixes checkpatch.pl warning:

Missing a blank line after declarations.

Signed-off-by: Gimcuan Hui <gimcuan@gmail.com>
Acked-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>