staging: ced401: fix double unlock bug

After spin_lock() is called, all of if-else conditions in this brace
should reach the end of else and spin_unlock() must be called.
So It doesn't need to call spin_unlock() without a return statement
for handling an error.

Also sparse says:
drivers/staging/ced1401/usb1401.c:1080:28: warning:
 context imbalance in 'Handle1401Esc' - unexpected unlock

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daeseok Youn <daeseok.youn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>