ice: check for XDP rings instead of bpf program when unconfiguring

If VSI rebuild is pending, .ndo_bpf() can attach/detach the XDP program on
VSI without applying new ring configuration. When unconfiguring the VSI, we
can encounter the state in which there is an XDP program but no XDP rings
to destroy or there will be XDP rings that need to be destroyed, but no XDP
program to indicate their presence.

When unconfiguring, rely on the presence of XDP rings rather then XDP
program, as they better represent the current state that has to be
destroyed.

Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Chandan Kumar Rout <chandanx.rout@intel.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>