USB: usb-storage: added missing MODULE_LICENSE("GPL") for usb-storage ums-* modules

The lack of a MODULE_LICENSE macro in ums-* subdrivers prevented them
from loading. Needs to be applied after Alan Stern's usb-storage
subdriver separation patchset. Also added missing MODULE_DESCRIPTION and
MODULE_AUTHOR entries.

Signed-off-by: Maciej Grela <maciej.grela@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>