coccinelle: Enable patching of missing __align_stack_8
coccinelle: Enable patching of missing __align_stack_8

Until now, aligned.cocci was only able to find missing __align_stack_8,
not patch them. This was due to the limited support of Coccinelle for
attributes, in particular the inability to match them. That made it
difficult to prevent the addition of __align_stack_8s where they were
already present, resulting in

  struct x_t x __align_stack_8 __align_stack_8 = {};

One of Coccinelle's authors proposed a workaround for this [1], with the
use of 'disable optional_attributes'. This commit implements that.

1 - https://systeme.lip6.fr/pipermail/cocci/2020-April/007318.html
Signed-off-by: Paul Chaignon <a027184a55211cd23e3f3094f1fdc728df5e0500@cilium.io>

tklauser/cilium,tgraf/cilium,cilium-team/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,cilium/cilium,cilium/cilium,tklauser/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,tklauser/cilium,cilium-team/cilium,cilium/cilium