clk: at91: sckc: add support to free slow oscillator

Add support to free slow oscillator resources.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/at91/sckc.c

@@ -161,6 +161,14 @@ at91_clk_register_slow_osc(void __iomem *sckcr,
 	return hw;
 }
 
+static void at91_clk_unregister_slow_osc(struct clk_hw *hw)
+{
+	struct clk_slow_osc *osc = to_clk_slow_osc(hw);
+
+	clk_hw_unregister(hw);
+	kfree(osc);
+}
+
 static unsigned long clk_slow_rc_osc_recalc_rate(struct clk_hw *hw,
 						 unsigned long parent_rate)
 {