usb: dwc3: Move CONFIG_USB_DWC3_GADGET/HOST to Kconfig

Description was borrowed from kernel dwc3 Kconfig.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
diff --git a/configs/omap5_uevm_defconfig b/configs/omap5_uevm_defconfig
index 024de72..5ab2b9d 100644
--- a/configs/omap5_uevm_defconfig
+++ b/configs/omap5_uevm_defconfig
@@ -9,6 +9,7 @@
 CONFIG_SYS_NS16550=y
 CONFIG_USB=y
 CONFIG_USB_DWC3=y
+CONFIG_USB_DWC3_GADGET=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_OF_LIBFDT=y