net/octeontx2: allow vector processing packets not by 4

net/octeontx2: allow vector processing packets not by 4

Current vector mode implementation floor-aligns pkt count
with NIX_DESCS_PER_LOOP and process that many packets.

Patch addresses the case where pkt count modulo NIX_DESCS_PER_LOOP
is non-zero, after the vector mode processing, scalar routine is
used to process if there are any leftover packets. Scalar routine
is also used when descriptor head is about to wrap and turn out to
be unaligned.

Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
Signed-off-by: Nithin Dabilpuram <ndabilpuram@marvell.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>