usb: isp1760: Move driver from drivers/usb/host/ to drivers/usb/isp1760/

Now that this is DRD, it doesn't make sense to keep it under
drivers/usb/host.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index ae481c3..8ed451d 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -104,6 +104,8 @@
 
 source "drivers/usb/chipidea/Kconfig"
 
+source "drivers/usb/isp1760/Kconfig"
+
 comment "USB port drivers"
 
 if USB