Fix incongruency in handling of sysfs entries creation.
This issue could cause invalid memory accesses, by not properly
detecting the end of the sysfs attributes array.

Fixes: 84c45d5f ("staging: gasket: Replace macro __ATTR with __ATTR_NULL")
Signed-off-by: Luis Mendes <luis.p.mendes@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200403151534.20753-1-luis.p.mendes@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>