Convert CONFIG_USB_MUSB_HCD et al to Kconfig

This converts the following to Kconfig:
   CONFIG_USB_MUSB_HCD
   CONFIG_USB_MUSB_UDC
   CONFIG_USB_DAVINCI
   CONFIG_USB_OMAP3
   CONFIG_USB_DA8XX
   CONFIG_USB_AM35X

Signed-off-by: Adam Ford <aford173@gmail.com>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index e7658b4..13e9e49 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -51,6 +51,8 @@
 
 source "drivers/usb/dwc3/Kconfig"
 
+source "drivers/usb/musb/Kconfig"
+
 source "drivers/usb/musb-new/Kconfig"
 
 source "drivers/usb/emul/Kconfig"