phy: phy-mtk-tphy: add support for phy type switch

Add support for PHY type switch via the mediatek topmisc syscon.

This is needed on mt7981 to make the PCIe correctly work and display
LinkUp.

Follow the same implementation done on Linux kernel with the usage of
the mediatek,syscon-type property.

Example:

u3port0: usb-phy@11e10700 {
	reg = <0x11e10700 0x900>;
	clocks = <&topckgen CK_TOP_USB3_PHY_SEL>;
	clock-names = "ref";
	#phy-cells = <1>;
	mediatek,syscon-type = <&topmisc 0x218 0>;
	status = "okay";
};

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 8f76787..e12347e 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -263,6 +263,8 @@
 	bool "MediaTek T-PHY Driver"
 	depends on PHY
 	depends on ARCH_MEDIATEK || SOC_MT7621
+	select REGMAP
+	select SYSCON
 	help
 	  MediaTek T-PHY driver supports usb2.0, usb3.0 ports, PCIe and
 	  SATA, and meanwhile supports two version T-PHY which have