Use proper acronym UPnP rather than UPNP

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Sources/VLCLocalServerListViewController.m

@@ -87,7 +87,7 @@
 /*    if (SYSTEM_RUNS_IOS7_OR_LATER)
         _sectionHeaderTexts = @[@"Universal Plug'n'Play (UPNP)", @"File Transfer Protocol (FTP)", @"Network Streams (SAP)"];
     else*/
-        _sectionHeaderTexts = @[@"Universal Plug'n'Play (UPNP)", @"Plex Media Server (via Bonjour)", @"File Transfer Protocol (FTP)"];
+        _sectionHeaderTexts = @[@"Universal Plug'n'Play (UPnP)", @"Plex Media Server (via Bonjour)", @"File Transfer Protocol (FTP)"];
 
     _backToMenuButton = [UIBarButtonItem themedRevealMenuButtonWithTarget:self andSelector:@selector(goBack:)];
     self.navigationItem.leftBarButtonItem = _backToMenuButton;