Failure of the UCAST set for base mac address fails when user configures a
duplicate mac address that matches that of another vNIC on the same port.
The bna does not handle the ucast failure and keeps this address in cache.
On disable of the vNIC, bna tries to delete the failed base mac address and the
fw asserts.

On failure of ucast address, mark ucast address set to false.
Signed-off-by: Rasesh Mody <rmody@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>