Convert CONFIG_USB_GADGET_DWC2_OTG_PHY to Kconfig

This converts the following to Kconfig:
   CONFIG_USB_GADGET_DWC2_OTG_PHY

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/s5p_goni_defconfig b/configs/s5p_goni_defconfig
index 17bd842..c13602d 100644
--- a/configs/s5p_goni_defconfig
+++ b/configs/s5p_goni_defconfig
@@ -61,5 +61,6 @@
 CONFIG_USB_GADGET_VENDOR_NUM=0x04e8
 CONFIG_USB_GADGET_PRODUCT_NUM=0x6601
 CONFIG_USB_GADGET_DWC2_OTG=y
+CONFIG_USB_GADGET_DWC2_OTG_PHY=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_USB_FUNCTION_THOR=y