bnxt_en: Add bnxt_fw_reset_timeout() helper.

This code to check if we have reached the maximum wait time after
firmware reset is used multiple times.  Add a helper function to
do this.

Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>