USB: auerswald possible memleak fix

fix possible memory leak in auerbuf_setup().

Regards,

	Mariusz Kozlowski

Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Wolfgang Muees <wolfgang@iksw-muees.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>