USB: keyspan: Remove duplicate device entries

The 28xb, as documented in comments, has the same ID's as the 28x.
Remove the duplicated ID's from the device tables, and expand the
comment to document this.
Signed-off-by: Ben Collins <ben.collins@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/keyspan.h

@@ -138,7 +138,8 @@ static int  keyspan_usa67_send_setup	(struct usb_serial *serial,
 
 /* Product IDs post-renumeration.  Note that the 28x and 28xb
    have the same id's post-renumeration but behave identically
-   so it's not an issue. */
+   so it's not an issue. As such, the 28xb is not listed in any
+   of the device tables. */
 #define	keyspan_usa18x_product_id		0x0112
 #define	keyspan_usa19_product_id		0x0107
 #define	keyspan_usa19qi_product_id		0x010c
@@ -482,7 +483,6 @@ static struct usb_device_id keyspan_ids_combined[] = {
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28x_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28xa_product_id) },
-	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28xb_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28xg_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa49w_product_id)},
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa49wlc_product_id)},
@@ -532,7 +532,6 @@ static struct usb_device_id keyspan_2port_ids[] = {
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28x_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28xa_product_id) },
-	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28xb_product_id) },
 	{ USB_DEVICE(KEYSPAN_VENDOR_ID, keyspan_usa28xg_product_id) },
 	{ } /* Terminating entry */
 };