5255 uts shouldn't open-code ISP2

@@ -17,10 +17,11 @@
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include <sys/sysmacros.h>
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/signal.h>
 #include <sys/stream.h>
 #include <sys/termio.h>

@@ -2643,16 +2644,12 @@
         ht_info->ampdu_factor = ATH9K_HT_CAP_MAXRXAMPDU_65536;
         ht_info->ampdu_density = ATH9K_HT_CAP_MPDUDENSITY_8;
 
         /* set up supported mcs set */
         (void) memset(&ht_info->rx_mcs_mask, 0, sizeof (ht_info->rx_mcs_mask));
-        tx_streams =
-            !(sc->sc_ah->ah_caps.tx_chainmask &
-            (sc->sc_ah->ah_caps.tx_chainmask - 1)) ? 1 : 2;
-        rx_streams =
-            !(sc->sc_ah->ah_caps.rx_chainmask &
-            (sc->sc_ah->ah_caps.rx_chainmask - 1)) ? 1 : 2;
+        tx_streams = ISP2(sc->sc_ah->ah_caps.tx_chainmask) ? 1 : 2;
+        rx_streams = ISP2(sc->sc_ah->ah_caps.rx_chainmask) ? 1 : 2;
 
         ht_info->rx_mcs_mask[0] = 0xff;
         if (rx_streams >= 2)
                 ht_info->rx_mcs_mask[1] = 0xff;
 }