rtl8xxxu: Implement 8723bu specific disable_rf() function

Powering up the 8723bu RF should probably be matched by the ability to
power it down again.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
index 776fd17..9c535e8 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
@@ -1266,6 +1266,7 @@
 	void (*init_aggregation) (struct rtl8xxxu_priv *priv);
 	void (*init_statistics) (struct rtl8xxxu_priv *priv);
 	void (*enable_rf) (struct rtl8xxxu_priv *priv);
+	void (*disable_rf) (struct rtl8xxxu_priv *priv);
 	void (*set_tx_power) (struct rtl8xxxu_priv *priv, int channel,
 			      bool ht40);
 	void (*update_rate_mask) (struct rtl8xxxu_priv *priv,