selinux: update parameter documentation

security/selinux/include/audit.h:54: warning: Function parameter or member 'krule' not described in 'selinux_audit_rule_known'
security/selinux/include/audit.h:54: warning: Excess function parameter 'rule' description in 'selinux_audit_rule_known'
security/selinux/include/avc.h:130: warning: Function parameter or member 'state' not described in 'avc_audit'

This also bring the parameter name of selinux_audit_rule_known() in sync
between declaration and definition.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>