ice: xsk: Fix cleaning of XDP_TX frames

ice: xsk: Fix cleaning of XDP_TX frames

Incrementation of xsk_frames inside the for-loop produces
infinite loop, if we have both normal AF_XDP-TX and XDP_TXed
buffers to complete.

Split xsk_frames into 2 variables (xsk_frames and completed_frames)
to eliminate this bug.

Fixes: 29322791bc8b ("ice: xsk: change batched Tx descriptor cleaning")
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Acked-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://lore.kernel.org/r/20230209160130.1779890-1-larysa.zaremba@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>