ft600.c: Drop width check, code below has no check.

The lower code would have crashed if width was NULL, so 'width == NULL' never
happens.

rigs/yaesu/ft600.c

@@ -467,10 +467,7 @@ int ft600_get_mode(RIG *rig, vfo_t vfo, rmode_t *mode, pbwidth_t *width)
         return -RIG_EINVAL;
     }
 
-    if (width != NULL)
-    {
-        *width = RIG_PASSBAND_NORMAL;
-    }
+    *width = RIG_PASSBAND_NORMAL;
 
     ret = ft600_read_status(rig);