phy: qcom-ufs: Make ufs_qcom_phy_disable_iface_clk static

Fix sparse warning:

drivers/phy/qualcomm/phy-qcom-ufs.c:462:6:
 warning: symbol 'ufs_qcom_phy_disable_iface_clk' was not declared. Should it be static?
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/qualcomm/phy-qcom-ufs.c

@@ -459,7 +459,7 @@ static int ufs_qcom_phy_enable_iface_clk(struct ufs_qcom_phy *phy)
 }
 
 /* Turn OFF M-PHY RMMI interface clocks */
-void ufs_qcom_phy_disable_iface_clk(struct ufs_qcom_phy *phy)
+static void ufs_qcom_phy_disable_iface_clk(struct ufs_qcom_phy *phy)
 {
 	if (phy->is_iface_clk_enabled) {
 		clk_disable_unprepare(phy->tx_iface_clk);