staging: gdm7240: adding LTE USB driver

GCT Semiconductor GDM7240 is 4G LTE chip.
This driver supports GCT reference platform as a USB device.

Signed-off-by: Won Kang <wonkang@gctsemi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
20 files changed