USB: fix gadgetfs class request delegation

gadgetfs (drivers/usb/gadget/inode.c) was not delegating all
non-device requests to userspace.  This patch makes the handling of
all request cases consistent.

Signed-off-by: Roy Hashimoto <hashimot@alumni.caltech.edu>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>