phy: stm32: defer probe for reset controller

Change stm32-usbphyc driver to defer its probe when the expected reset
control has its probe operation deferred.
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Link: https://lore.kernel.org/r/20201110102305.27205-2-amelie.delaunay@st.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/st/phy-stm32-usbphyc.c

@@ -340,6 +340,10 @@ static int stm32_usbphyc_probe(struct platform_device *pdev)
 		reset_control_assert(usbphyc->rst);
 		udelay(2);
 		reset_control_deassert(usbphyc->rst);
+	} else {
+		ret = PTR_ERR(usbphyc->rst);
+		if (ret == -EPROBE_DEFER)
+			goto clk_disable;
 	}
 
 	usbphyc->switch_setup = -EINVAL;