qlcnic: fix a timeout loop

The problem here is that at the end of the loop we test for if
idc->vnic_wait_limit is zero, but since idc->vnic_wait_limit-- is a
post-op, it actually ends up set to (u8)-1.  I have fixed this by
moving the decrement inside the loop.

Fixes: 486a5bc7

 ('qlcnic: Add support for 83xx suspend and resume.')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>