dplayx: Cast-qual warning fix

[Andrew Talbot]

Changelog:
    dplayx: Cast-qual warning fix.

diff -urN a/dlls/dplayx/dplobby.c b/dlls/dplayx/dplobby.c
--- a/dlls/dplayx/dplobby.c	2007-03-08 21:37:04.000000000 +0000
+++ b/dlls/dplayx/dplobby.c	2007-07-19 22:00:40.000000000 +0100
@@ -694,7 +694,7 @@
     /* Invoke the enum method. If false is returned, stop enumeration */
     if ( !lpEnumAddressCallback( &lpElements->guidDataType,
                                  lpElements->dwDataSize,
-                                 (BYTE*)lpElements + sizeof( DPADDRESS ),
+                                 (const BYTE *)lpElements + sizeof( DPADDRESS ),
                                  lpContext ) )
     {
       break;