staging: wlan-ng: Remove unused function pointer typedef freebuf_method_t

Remove the 'freebuf_method_t' typedef as it is not used.
Signed-off-by: Chen Lin <chen.lin5@zte.com.cn>
Link: https://lore.kernel.org/r/1613447646-4678-1-git-send-email-chen45464546@163.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wlan-ng/p80211conv.h

@@ -122,9 +122,6 @@ struct p80211_caphdr {
 	__be32 encoding;
 };
 
-/* buffer free method pointer type */
-typedef void (*freebuf_method_t) (void *buf, int size);
-
 struct p80211_metawep {
 	void *data;
 	u8 iv[4];