usb: dwc3: exynos: add support for exynos7870

Exynos7870 devices have a DWC3 compatible USB 2.0 controller.
Add support in the driver by:
 - Adding its own compatible string, "samsung,exynos7870-dwusb3".
 - Adding three USBDRD clocks named "bus_early", "ref", and "ctrl", to
   be controlled by the driver.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250301-exynos7870-usb-v3-2-f01697165d19@disroot.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Kaustabh Chakraborty

drivers/usb/dwc3/dwc3-exynos.c

@@ -163,6 +163,12 @@ static const struct dwc3_exynos_driverdata exynos7_drvdata = {
 	.suspend_clk_idx = 1,
 };
 
+static const struct dwc3_exynos_driverdata exynos7870_drvdata = {
+	.clk_names = { "bus_early", "ref", "ctrl" },
+	.num_clks = 3,
+	.suspend_clk_idx = -1,
+};
+
 static const struct dwc3_exynos_driverdata exynos850_drvdata = {
 	.clk_names = { "bus_early", "ref" },
 	.num_clks = 2,
@@ -185,6 +191,9 @@ static const struct of_device_id exynos_dwc3_match[] = {
 	}, {
 		.compatible = "samsung,exynos7-dwusb3",
 		.data = &exynos7_drvdata,
+	}, {
+		.compatible = "samsung,exynos7870-dwusb3",
+		.data = &exynos7870_drvdata,
 	}, {
 		.compatible = "samsung,exynos850-dwusb3",
 		.data = &exynos850_drvdata,