ice: Fix XDP memory leak when NIC is brought up and down

Fix the buffer leak that occurs while switching
the port up and down with traffic and XDP by
checking for an active XDP program and freeing all empty TX buffers.

Fixes: efc2214b ("ice: Add support for XDP")
Signed-off-by: Kamil Maziarz <kamil.maziarz@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com> (A Contingent Worker at Intel)
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>