cfg80211: fix spelling mistake: "uknown" -> "unknown"

Trivial fix to spelling mistake in pr_debug message text
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/reg.c

@@ -3399,7 +3399,7 @@ bool reg_supported_dfs_region(enum nl80211_dfs_regions dfs_region)
 	case NL80211_DFS_JP:
 		return true;
 	default:
-		pr_debug("Ignoring uknown DFS master region: %d\n", dfs_region);
+		pr_debug("Ignoring unknown DFS master region: %d\n", dfs_region);
 		return false;
 	}
 }