staging: gasket: sysfs: fix attribute release comment

Comments for gasket_sysfs_get_attr() incorrectly describe reference
release procedure.

Signed-off-by: Nick Ewalt <nicholasewalt@google.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>