usb: dwc3: remove dwc3 dependency on host AND gadget.

DWC3 controller curretly depends on USB && USB_GADGET.
Some hardware may like to use only host feature on dwc3,
or only gadget feature.

So, removing this dependency of USB_DWC3 on USB and USB_GADGET.
Adding the mode of operaiton of DWC3 also here
HOST/GADGET/DUAL_ROLE based on which features are enabled.

[ balbi@ti.com :
	. make sure we have default modes for all possible Kernel
		configurations.
	. Remove the config -> menuconfig change as it's unnecessary
	. switch over to IS_ENABLED() ]

CC: Doug Anderson <dianders@chromium.org>
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index f6a6e07..77e3f40 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -1,6 +1,6 @@
 config USB_DWC3
 	tristate "DesignWare USB3 DRD Core Support"
-	depends on (USB && USB_GADGET)
+	depends on (USB || USB_GADGET)
 	select USB_OTG_UTILS
 	select USB_XHCI_PLATFORM if USB_SUPPORT && USB_XHCI_HCD
 	help
@@ -12,6 +12,35 @@
 
 if USB_DWC3
 
+choice
+	bool "DWC3 Mode Selection"
+	default USB_DWC3_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_DWC3_HOST if (USB && !USB_GADGET)
+	default USB_DWC3_GADGET if (!USB && USB_GADGET)
+
+config USB_DWC3_HOST
+	bool "Host only mode"
+	depends on USB
+	help
+	  Select this when you want to use DWC3 in host mode only,
+	  thereby the gadget feature will be regressed.
+
+config USB_DWC3_GADGET
+	bool "Gadget only mode"
+	depends on USB_GADGET
+	help
+	  Select this when you want to use DWC3 in gadget mode only,
+	  thereby the host feature will be regressed.
+
+config USB_DWC3_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on (USB && USB_GADGET)
+	help
+	  This is the default mode of working of DWC3 controller where
+	  both host and gadget features are enabled.
+
+endchoice
+
 config USB_DWC3_DEBUG
 	bool "Enable Debugging Messages"
 	help