drivers/net/wireless: fix sparse warnings: fix signedness

Fix this sparse warnings:
  drivers/net/wireless/airo.c:2102:21: warning: incorrect type in initializer (different signedness)
  drivers/net/wireless/airo.c:2126:21: warning: incorrect type in initializer (different signedness)
  drivers/net/wireless/airo.c:2167:21: warning: incorrect type in initializer (different signedness)
  drivers/net/wireless/airo.c:2191:21: warning: incorrect type in initializer (different signedness)
Signed-off-by: NHannes Eder <hannes@hanneseder.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/wireless/airo.c

@@ -1161,7 +1161,7 @@ struct airo_info {
 	   use the high bit to mark whether it is in use. */
 #define MAX_FIDS 6
 #define MPI_MAX_FIDS 1
-	int                           fids[MAX_FIDS];
+	u32                           fids[MAX_FIDS];
 	ConfigRid config;
 	char keyindex; // Used with auto wep
 	char defindex; // Used with auto wep