Remove "frame size must be a multiple of 2" check.

This check only caught explicitly set sizes from the cmd line and overriding
the users wish seems silly, especially as it seems to work.

Originally committed as revision 20634 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -2486,10 +2486,6 @@ static void opt_frame_size(const char *arg)
         fprintf(stderr, "Incorrect frame size\n");
         av_exit(1);
     }
-    if ((frame_width % 2) != 0 || (frame_height % 2) != 0) {
-        fprintf(stderr, "Frame size must be a multiple of 2\n");
-        av_exit(1);
-    }
 }
 
 static void opt_pad_color(const char *arg) {