staging: brcm80211: replaced typedef wlc_rateset_t

By struct brcms_c_rateset. Struct brcms_c_rateset was renamed from
brcms_rateset, because there will be two rateset related structures that
should differ significantly in naming from each other. Struct wl_rateset
will be renamed to struct brcm_rateset in the next patch.

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>