Banshee: disable SVGA video processing (set svga->fb_only) when video

processor is enabled. Fixes corrupt desktop introduced by recent SVGA
mapping changes.

src/vid_voodoo_banshee.c

@@ -147,6 +147,7 @@ enum
 
 #define VGAINIT0_EXTENDED_SHIFT_OUT (1 << 12)
 
+#define VIDPROCCFG_VIDPROC_ENABLE (1 << 0)
 #define VIDPROCCFG_CURSOR_MODE (1 << 1)
 #define VIDPROCCFG_HALF_MODE (1 << 4)
 #define VIDPROCCFG_OVERLAY_ENABLE (1 << 8)
@@ -476,6 +477,8 @@ static void banshee_recalctimings(svga_t *svga)
                 svga->video_res_override = 0;
         }
 
+        svga->fb_only = (banshee->vidProcCfg & VIDPROCCFG_VIDPROC_ENABLE);
+
         if (((svga->miscout >> 2) & 3) == 3)
         {
                 int k = banshee->pllCtrl0 & 3;