Force re-seek on disc loading - fixes issues with disc change not seen on some models.

src/disc.c

@@ -93,6 +93,7 @@ void disc_load(int drive, char *fn)
                         drive_empty[drive] = 0;
                         disc_changed[drive] = 1;
                         strcpy(discfns[drive], fn);
+                        fdd_seek(drive, 0);
                         return;
                 }
                 c++;