USB: more serial drivers writing after disconnect

this covers the rest of the obvious cases by using the flags
and locks to guard against disconnect which were introduced
in the earlier patch against mos7720.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --cc drivers/usb/serial/airprime.c
Simple merge

diff --cc drivers/usb/serial/cp2101.c
Simple merge

diff --cc drivers/usb/serial/ftdi_sio.c
Simple merge

diff --cc drivers/usb/serial/garmin_gps.c
Simple merge

diff --cc drivers/usb/serial/visor.c
Simple merge