cnic: Fix interrupt logic

We need to keep looping until cnic_get_kcqes() returns 0.  cnic_get_kcqes()
returns a maximum of 64 entries.  If there are more entries in the queue
and we don't loop back, the remaining entries may not be serviced for a
long time.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>