The driver may sleep under a spinlock.
The function call path is:
rr_close (acquire the spinlock)
  free_irq --> may sleep

To fix it, free_irq is moved to the place without holding the spinlock.

This bug is found by my static analysis tool(DSAC) and checked by my code review.
Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>