ice: Ignore EEXIST when setting promisc mode

Ignore EEXIST error when setting promiscuous mode.
This fix is needed because the driver could set promiscuous mode
when it still has not cleared properly.
Promiscuous mode could be set only once, so setting it second
time will be rejected.

Fixes: 5eda8afd

 ("ice: Add support for PF/VF promiscuous mode")
Signed-off-by: Grzegorz Siwik <grzegorz.siwik@intel.com>
Link: https://lore.kernel.org/all/CAK8fFZ7m-KR57M_rYX6xZN39K89O=LGooYkKsu6HKt0Bs+x6xQ@mail.gmail.com/
Tested-by: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Tested-by: Igor Raits <igor@gooddata.com>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>