net/bnx2x: fix packet drop

net/bnx2x: fix packet drop

Patch "8bd31421c593 ("net/bnx2x: fix ramrod timeout")"
introduced a regression where sc->scan_fp flags is
set for unexpectedly long time. So the slow path completion
handler flow is run unnecessarily which walks over receive
descriptor ring of fast path and drops the data packets while looking
for slow path completion descriptor out of fast path ring.

This issue is seen under heavy traffic with link events happening
in background.

Fixes: 8bd31421c593 ("net/bnx2x: fix ramrod timeout")
Cc: stable@dpdk.org
Signed-off-by: Shahed Shaikh <shshaikh@marvell.com>
Acked-by: Rasesh Mody <rmody@marvell.com>