cfg80211: re-enable 5/10 MHz support

Unfortunately I forgot this during the merge window, but the
patch seems small enough to go in as a fix. The userspace API
bug that was the reason for disabling it has long been fixed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/core.c

@@ -440,9 +440,6 @@ int wiphy_register(struct wiphy *wiphy)
 	int i;
 	u16 ifmodes = wiphy->interface_modes;
 
-	/* support for 5/10 MHz is broken due to nl80211 API mess - disable */
-	wiphy->flags &= ~WIPHY_FLAG_SUPPORTS_5_10_MHZ;
-
 	/*
 	 * There are major locking problems in nl80211/mac80211 for CSA,
 	 * disable for all drivers until this has been reworked.