net/qede: remove flags from Tx entry

net/qede: remove flags from Tx entry

Each sw_tx_ring entry was of type struct qede_tx_entry:

struct qede_tx_entry {
       struct rte_mbuf *mbuf;
       uint8_t flags;
};

Leaving the unused flags member here has a few performance implications.
First, each qede_tx_entry takes up more memory which has caching
implications as less entries fit in a cache line while multiple entries
are frequently handled in batches. Second, an array of qede_tx_entry
entries is incompatible with existing APIs that expect an array of
rte_mbuf pointers. Consequently, an extra array need to be allocated
before calling such APIs and each entry needs to be copied over.

This patch omits the flags field and replaces the qede_tx_entry entry
by a simple rte_mbuf pointer.

Signed-off-by: Balazs Nemeth <bnemeth@redhat.com>
Reviewed-by: Igor Russkikh <irusskikh@marvell.com>