AppArmor: fix task_setrlimit prototype

After rlimits tree was merged we get the following errors:
security/apparmor/lsm.c:663:2: warning: initialization from incompatible pointer type

It is because AppArmor was merged in the meantime, but uses the old
prototype. So fix it by adding struct task_struct as a first parameter
of apparmor_task_setrlimit.

NOTE that this is ONLY a compilation warning fix (and crashes caused
by that). It needs proper handling in AppArmor depending on who is the
'task'.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>