apparmor: Fix some kernel-doc comments

Remove some warnings found by running scripts/kernel-doc,
which is caused by using 'make W=1'.

security/apparmor/domain.c:137: warning: Function parameter or member
'state' not described in 'label_compound_match'
security/apparmor/domain.c:137: warning: Excess function parameter
'start' description in 'label_compound_match'
security/apparmor/domain.c:1294: warning: Excess function parameter
'onexec' description in 'aa_change_profile'

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>