plugins/ad9371: remove unnecessary call to iio_widget_update

this call caused the value for RX2 gain in the spin box to be overwritten
unless the Enter key was pressed
now spin box for RX2 gain behaves like RX1 gain

Signed-off-by: Cristina Suteu <[email protected]>

Author: cristina-suteu

Diff for: plugins/ad9371.c

@@ -729,8 +729,6 @@ static gboolean update_display(gpointer foo)
 			clgc_update_labels();
 			vswr_update_labels();
 		}
-
-		iio_widget_update(&rx_widgets[rx2_gain]);
 	}
 
 	return TRUE;