net/bnxt: use appropriate type for Rx ring

net/bnxt: use appropriate type for Rx ring

Change the type of the software receive mbuf ring from an array
of structures containing an mbuf pointer to an array of pointers
to struct rte_mbuf for consistency with how this ring is currently
used by the vector mode receive function.

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