Abstract bus layer brcmf_bus_txdata function pointer for common
layer. This patch is part of the fullmac bus interface refactoring.
Reviewed-by: NPieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: NArend van Spriel <arend@broadcom.com>
Reviewed-by: NAlwin Beukers <alwin@broadcom.com>
Signed-off-by: NFranky Lin <frankyl@broadcom.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>