staging: brcm80211: removed function declaration typedefs from dma.h part 2

Softmac related code cleanup. Typedefs are undesirable according to the
CodingStyle document.

Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>