net/bnxt: validate structs and pointers before use

net/bnxt: validate structs and pointers before use

Validate pointers aren't pointing to uninitialized areas
including txq and rxq before using them to avoid
bnxt driver from crashing.

Signed-off-by: Rahul Gupta <rahul.gupta@broadcom.com>
Signed-off-by: Jay Ding <jay.ding@broadcom.com>
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Randy Schacher <stuart.schacher@broadcom.com>
Tested-by: Randy Schacher <stuart.schacher@broadcom.com>