if_bnxt: Pass HWRM cmd response to apps even if FW fails it

[sumit.saxena_broadcom.com]

Summary

The driver was not passing the HWRM command response to management
apps when the firmware failed the command, which is not what apps
expect. Copy the response out whenever firmware populated one
(resp_len != 0), regardless of the command's overall return code, and
stop bailing out of the mgmt ioctl path early on a failed passthrough
so DMA'd indirect data and the response still get copied to
userspace.