net/bnxt: remove assert for zero data length in Tx

net/bnxt: remove assert for zero data length in Tx

Currently the PMD tries to detect a potential 0 byte DMA by
using RTE_VERIFY.
But since RTE_VERIFY internally calls rte_panic() it is fatal to
the application and some applications want to avoid that.
So return an error from the bnxt xmit handler if such a bad pkt is
encountered by logging an error message, dumping the pkt header and
dump the current stack as well

Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>