Fix memory leak in the gpio sysfs interface due to failure to drop
reference to device returned by class_find_device when creating a link.

Fixes: a4177ee7 ("gpiolib: allow exported GPIO nodes to be named
using sysfs links")
Cc: stable <[email protected]>	# v2.6.32
Signed-off-by: Johan Hovold <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>