usb: dwc3: Move CONFIG_USB_DWC3_OMAP to Kconfig

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
diff --git a/configs/am437x_gp_evm_defconfig b/configs/am437x_gp_evm_defconfig
index 8dc905e..ce16f93 100644
--- a/configs/am437x_gp_evm_defconfig
+++ b/configs/am437x_gp_evm_defconfig
@@ -23,5 +23,6 @@
 CONFIG_USB=y
 CONFIG_USB_DWC3=y
 CONFIG_USB_DWC3_GADGET=y
+CONFIG_USB_DWC3_OMAP=y
 CONFIG_USB_GADGET=y
 CONFIG_USB_GADGET_DOWNLOAD=y