staging: brcm80211: rename struct dhd_pub to struct brcmf_pub

The structure dhd_pub has been renamed to have more consistent naming
in the fullmac driver. This also remove the type definition for this
structure.

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