brcmfmac: For FW signalling it is necessary to track gen bit.

Store gen bit on suppressed packet per entry and use latest
stored version for each packet which gets transmitted to fw.

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>