During P2P testing it turned out that the firmware sents multiple
multiple creditmap event messages. Only the first message from the
firmware should be processed. Otherwise the firmware-signalled flow
control can run haywire when it has packets outstanding in firmware.
Reviewed-by: Arend Van Spriel <arend@broadcom.com> Signed-off-by: Hante Meuleman <meuleman@broadcom.com> Signed-off-by: Arend van Spriel <arend@broadcom.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>