psmouse_reconnect() will not be called if psmouse driver is not bound to
the serio port, so there is no point in checking that.  Also, as coded, it
introduces potential NULL dereference in psmouse_dbg() in case psmouse is
indeed NULL. Let's just remove it.

Detected by Coverity: CID 146528
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>