net/bnxt: improve vector Tx
net/bnxt: improve vector Tx

Improve performance of vector burst transmit function by processing
multiple packets per inner loop iteration.

Reviewed-by: Ajit Khaparde <01965fbd61169dc18f3fb5e13de7f67d298f8924@broadcom.com>
Signed-off-by: Lance Richardson <4e26776f5588f0e1c0c16cd2ddc0e9efc79c5b3a@broadcom.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk