dpaa_eth: small leak on error

This should be >= instead of > here.  It means that we don't increment
the free count enough so it becomes off by one.

Fixes: 9ad1a374 ("dpaa_eth: add support for DPAA Ethernet")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>