The hanger for firmware-signalling is used to retain information for
outstanding transmit packets that await tx status.
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com> Reviewed-by: Hante Meuleman <meuleman@broadcom.com> Reviewed-by: Piotr Haber <phaber@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>