USB: gadget section fixes

Restore some section annotations:  they were switched to "__devinit"
while they should have been "__init", because of bogus warnings.  The
warnings are now fixed, so the runtime footprint of various drivers
can now shrink a bit.  On ARMv5, it's about 600 bytes except for the
Ethernet gadget, where it can save a bit more.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>