nl80211: Fix undefined behavior in bit shift

Shifting signed 32-bit value by 31 bits is undefined.  Changing most
significant bit to unsigned.

Signed-off-by: Jiunn Chang <c0d1n61at3@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/uapi/linux/nl80211.h

@@ -5314,7 +5314,7 @@ enum nl80211_feature_flags {
 	NL80211_FEATURE_TDLS_CHANNEL_SWITCH		= 1 << 28,
 	NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR		= 1 << 29,
 	NL80211_FEATURE_SCHED_SCAN_RANDOM_MAC_ADDR	= 1 << 30,
-	NL80211_FEATURE_ND_RANDOM_MAC_ADDR		= 1 << 31,
+	NL80211_FEATURE_ND_RANDOM_MAC_ADDR		= 1U << 31,
 };
 
 /**