net/dpaa2: fix timestamping for IEEE1588

net/dpaa2: fix timestamping for IEEE1588

The current implementation of DPAA2 driver code is such
that it records Rx and Tx timestamp for PTP without checking
if they are PTP packets or not. Packets for which
RTE_MBUF_F_RX_IEEE1588_TMST and RTE_MBUF_F_TX_IEEE1588_TMST
is not set, Rx and Tx timestamp should not be recorded.

This patch fixes this issue by checking if the required
flags are set in the mbuf before recording timestamps.

Also this change defines separate values for
DPAA2_TX_CONF_ENABLE and DPAA2_NO_PREFETCH_RX

Fixes: e806bf878c17 ("net/dpaa2: support timestamp")
Cc: stable@dpdk.org
Signed-off-by: Vanshika Shukla <vanshika.shukla@nxp.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>