Fixes for fallback mbuf allocation logic.
   - Iterate over all processed descriptors (representor and
     non-representor) when checking allocation status.
   - Invoke fallback allocation logic when an allocation
     failure has occurred for any received packet, not
     just the last.

Based on upstream commit c86e9301 ("net/bnxt: fix fallback
mbuf allocation logic"), with changes to resolve conflicts caused
by the absence of upstream commit c7de4195 ("net/bnxt: modify
ring index logic")

Fixes: 6dc83230 ("net/bnxt: support port representor data path")
Fixes: d9dd0b29 ("net/bnxt: fix Rx handling and buffer allocation logic")
Cc: stable@dpdk.org

Signed-off-by: Lance Richardson <lance.richardson@broadcom.com>