staging: brcm80211: use correct pointer types in bcm_pktq_flush

to clarify the intention:

On Sun, May 15, 2011 at 09:54:26PM +0200, Arend van Spriel wrote:
> On 05/15/2011 08:10 PM, Hauke Mehrtens wrote:
[...]
>> Why don't you use the correct pointer type here instead of casting then
>> around and the parameter names are meaningless too.
>>
>> static bool cb_del_ampdu_pkt(struct sk_buff *mpdu, struct
>> cb_del_ampdu_pars *ampdu_pars)
[...]
> Actually this is a generic callback mechanism in which an additional
> parameter can be passed, which can be of *any* type hence a void pointer
> seems justified here and a meaningless name is used. I do agree that the
> txi parameter will always be a struct sk_buff and should be indicated as
> such.

Reported-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Clemens Noss <cnoss@gmx.de>
Acked-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>