ssb: implement spurious tone avoidance

And make use of it in b43. This fixes a regression introduced with
49d55cef5b
b43: N-PHY: implement spurious tone avoidance
This commit made BCM4322 use only MCS 0 on channel 13, which of course
resulted in performance drop (down to 0.7Mb/s).

Reported-by: Stefan Brüns <stefan.bruens@rwth-aachen.de>
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/b43/phy_n.c

@@ -5165,7 +5165,8 @@ static void b43_nphy_pmu_spur_avoid(struct b43_wldev *dev, bool avoid)
 #endif
 #ifdef CONFIG_B43_SSB
 	case B43_BUS_SSB:
-		/* FIXME */
+		ssb_pmu_spuravoid_pllupdate(&dev->dev->sdev->bus->chipco,
+					    avoid);
 		break;
 #endif
 	}