Convert CONFIG_USB_GADGET_AT91 to Kconfig

This converts the following to Kconfig:
   CONFIG_USB_GADGET_AT91

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/smartweb_defconfig b/configs/smartweb_defconfig
index 601353c..ed0ed2c 100644
--- a/configs/smartweb_defconfig
+++ b/configs/smartweb_defconfig
@@ -97,6 +97,7 @@
 CONFIG_USB_GADGET_MANUFACTURER="Siemens AG"
 CONFIG_USB_GADGET_VENDOR_NUM=0x0908
 CONFIG_USB_GADGET_PRODUCT_NUM=0x02d2
+CONFIG_USB_GADGET_AT91=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_WDT=y
 CONFIG_WDT_AT91=y
diff --git a/configs/taurus_defconfig b/configs/taurus_defconfig
index ef9e444..9a1dac7 100644
--- a/configs/taurus_defconfig
+++ b/configs/taurus_defconfig
@@ -115,6 +115,7 @@
 CONFIG_USB_GADGET_MANUFACTURER="Siemens AG"
 CONFIG_USB_GADGET_VENDOR_NUM=0x0908
 CONFIG_USB_GADGET_PRODUCT_NUM=0x02d2
+CONFIG_USB_GADGET_AT91=y
 CONFIG_USB_GADGET_DOWNLOAD=y
 CONFIG_WDT=y
 CONFIG_WDT_AT91=y
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index e8da73c..e120efe 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -82,6 +82,10 @@
 	help
 	  Enable the Broadcom UDC OTG physical device interface.
 
+config USB_GADGET_AT91
+	bool "Atmel AT91 USB Gadget Controller"
+	depends on ARCH_AT91
+
 config USB_GADGET_DWC2_OTG
 	bool "DesignWare USB2.0 HS OTG controller (gadget mode)"
 	select USB_GADGET_DUALSPEED
diff --git a/include/configs/smartweb.h b/include/configs/smartweb.h
index 7944759..b988b96 100644
--- a/include/configs/smartweb.h
+++ b/include/configs/smartweb.h
@@ -64,10 +64,6 @@
 #define CONFIG_USART_BASE		ATMEL_BASE_DBGU
 #define CONFIG_USART_ID			ATMEL_ID_SYS
 
-/* USB DFU support */
-
-#define CONFIG_USB_GADGET_AT91
-
 /* DFU class support */
 #define DFU_MANIFEST_POLL_TIMEOUT	25000
 
diff --git a/include/configs/taurus.h b/include/configs/taurus.h
index baaf94e..30f8425 100644
--- a/include/configs/taurus.h
+++ b/include/configs/taurus.h
@@ -62,10 +62,6 @@
 #endif
 
 #if defined(CONFIG_BOARD_TAURUS)
-/* USB DFU support */
-
-#define CONFIG_USB_GADGET_AT91
-
 /* DFU class support */
 #define DFU_MANIFEST_POLL_TIMEOUT	25000
 #endif