Change how the MIDI gadget 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>