[PATCH] USB: add driver for non-composite Sierra Wireless devices

This patch creates a new driver, sierra.c, that supports the new
non-composite Sierra Wireless WWAN devices. The older Sierra
Wireless and Airprime devices are supported in airprime.c.

Signed-off-by: Kevin Lloyd <linux@sierrawireless.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>