user32: Pad lfFaceName so we don't write uninitialised data to the registry.

Found by Valgrind.
diff --git a/dlls/user32/sysparams.c b/dlls/user32/sysparams.c
index 5113acb..c6cb494 100644
--- a/dlls/user32/sysparams.c
+++ b/dlls/user32/sysparams.c
@@ -699,7 +699,7 @@
 
 /* Convenience function to save logical fonts */
 static BOOL SYSPARAMS_SaveLogFont( LPCWSTR lpRegKey, LPCWSTR lpValName,
-                                   const LPLOGFONTW plf, UINT fWinIni )
+                                   const LOGFONTW *plf, UINT fWinIni )
 {
     LOGFONTW lf = *plf;
     int len;