usb: dwc3: core: Fix compile warning on s390 gcc in dwc3_get_phy call

Recent commit introduced support for reading Multiport PHYs and
while doing so iterated over an integer variable which runs from
[0-254] in the worst case scenario. But S390 compiler treats it as a
warning and complains that the integer write to string can go to 11
characters. Fix this by modifying iterator variable to u8.
Suggested-by: Johan Hovold <johan@kernel.org>
Fixes: 30a46746 ("usb: dwc3: core: Refactor PHY logic to support Multiport Controller")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404241215.Mib19Cu7-lkp@intel.com/Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20240426050512.57384-1-quic_kriskura@quicinc.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.c

@@ -1449,7 +1449,7 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
 	struct device_node	*node = dev->of_node;
 	char phy_name[9];
 	int ret;
-	int i;
+	u8 i;
 
 	if (node) {
 		dwc->usb2_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 0);
@@ -1479,7 +1479,7 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
 		if (dwc->num_usb2_ports == 1)
 			snprintf(phy_name, sizeof(phy_name), "usb2-phy");
 		else
-			snprintf(phy_name, sizeof(phy_name),  "usb2-%d", i);
+			snprintf(phy_name, sizeof(phy_name),  "usb2-%u", i);
 
 		dwc->usb2_generic_phy[i] = devm_phy_get(dev, phy_name);
 		if (IS_ERR(dwc->usb2_generic_phy[i])) {
@@ -1496,7 +1496,7 @@ static int dwc3_core_get_phy(struct dwc3 *dwc)
 		if (dwc->num_usb3_ports == 1)
 			snprintf(phy_name, sizeof(phy_name), "usb3-phy");
 		else
-			snprintf(phy_name, sizeof(phy_name), "usb3-%d", i);
+			snprintf(phy_name, sizeof(phy_name), "usb3-%u", i);
 
 		dwc->usb3_generic_phy[i] = devm_phy_get(dev, phy_name);
 		if (IS_ERR(dwc->usb3_generic_phy[i])) {