modedb: fix incorrect sync and vmode flags for CVT modes

The temporary structure for calculated CVT mode is not initialized.  Few
fields have only bits or-ed or and-ed so they may be left in incorrect
(random) state.

Testing of the tridentfb seems like a good exercise for the fbdev layer.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/modedb.c

@@ -590,6 +590,7 @@ done:
 		    "", (margins) ? " with margins" : "", (interlace) ?
 		    " interlaced" : "");
 
+	    memset(&cvt_mode, 0, sizeof(cvt_mode));
 	    cvt_mode.xres = xres;
 	    cvt_mode.yres = yres;
 	    cvt_mode.refresh = (refresh) ? refresh : 60;