brcmfmac: Signalling header push and pull on logic places.

Currently suppressed packets get enque-ed with header which
then gets pulled before transmit. It is more logical and clean
to pull the header on return and push it unconditionally on xmit.

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>