Rename the dpaa2_eth_xdp_release_buf function into dpaa2_eth_recycle_buf
since in the next patches we'll be using the same recycle mechanism for
the normal stack path beside for XDP_DROP.

Also, rename the array which holds the buffers to be recycled so that it
does not have any reference to XDP.
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>