ixgbe: xsk: change !netif_carrier_ok() handling in ixgbe_xmit_zc()

Commit c685c69f ("ixgbe: don't do any AF_XDP zero-copy transmit if
netif is not OK") addressed the ring transient state when
MEM_TYPE_XSK_BUFF_POOL was being configured which in turn caused the
interface to through down/up. Maurice reported that when carrier is not
ok and xsk_pool is present on ring pair, ksoftirqd will consume 100% CPU
cycles due to the constant NAPI rescheduling as ixgbe_poll() states that
there is still some work to be done.

To fix this, do not set work_done to false for a !netif_carrier_ok().

Fixes: c685c69f ("ixgbe: don't do any AF_XDP zero-copy transmit if netif is not OK")
Reported-by: Maurice Baijens <maurice.baijens@ellips.com>
Tested-by: Maurice Baijens <maurice.baijens@ellips.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>