Change how the Gadget Zero driver builds:  don't use
separate compilation, since it works poorly when key
parts are library code (with init sections etc).
Instead be as close as we can to "gcc --combine ...".
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>