usb: usb251xb: Add USB2517i specific struct and IDs

There are USB2517 and USB2517i hubs, which have almost the same
registers space as already supported USB251xBi series. The difference
it in DIDs and in a few functions. This patch adds the USB2517/i data
structures to the driver, so it would have different setting depending
on the device discovered on i2c-bus.

Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/Kconfig

@@ -238,8 +238,8 @@ config USB_HUB_USB251XB
 	depends on I2C
 	help
 	  This option enables support for configuration via SMBus of the
-	  Microchip USB251xB/xBi USB 2.0 Hub Controller series.
-	  Configuration parameters may be set in devicetree or platform data.
+	  Microchip USB251x/xBi USB 2.0 Hub Controller series. Configuration
+	  parameters may be set in devicetree or platform data.
 	  Say Y or M here if you need to configure such a device via SMBus.
 
 config USB_HSIC_USB3503