USB: add quirk to avoid config and interface strings

Apparently the Configuration and Interface strings aren't used as
often as the Vendor, Product, and Serial strings.  In at least one
device (a Saitek Cyborg Gold 3D joystick), attempts to read the
Configuration string cause the device to stop responding to Control
requests.

This patch (as1226) adds a quirks flag, telling the kernel not to
read a device's Configuration or Interface strings, together with a
new quirk for the offending joystick.

Reported-by: Melchior FRANZ <melchior.franz@gmail.com>
Tested-by: Melchior FRANZ <melchior.franz@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>  [2.6.28 and 2.6.29, nothing earlier]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 49e7f56..3922fa9 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1719,7 +1719,8 @@
 	}
 	kfree(new_interfaces);
 
-	if (cp->string == NULL)
+	if (cp->string == NULL &&
+			!(dev->quirks & USB_QUIRK_CONFIG_INTF_STRINGS))
 		cp->string = usb_cache_string(dev, cp->desc.iConfiguration);
 
 	/* Now that all the interfaces are set up, register them