octeontx2-pf: use xdp_return_frame() to free xdp buffers

xdp_return_frames() will help to free the xdp frames and their
associated pages back to page pool.

Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Signed-off-by: Suman Ghosh <sumang@marvell.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>