open() routine calls stop() in case of errors, the function will try
to free the requested IRQ. But we don't know if it was actually
requested, so the code might issue bogus free_irq(0, dev) call.

Fix this by rearranging the code so that now request_irq() is the last
call in the open() routine, and move free_irq() into the close().
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>