apparmor: Fix kernel-doc warnings in apparmor/lib.c

apparmor: Fix kernel-doc warnings in apparmor/lib.c

Fix kernel-doc warnings:

security/apparmor/lib.c:33: warning: Excess function parameter
'str' description in 'aa_free_str_table'
security/apparmor/lib.c:33: warning: Function parameter or member
't' not described in 'aa_free_str_table'
security/apparmor/lib.c:94: warning: Function parameter or
member 'n' not described in 'skipn_spaces'
security/apparmor/lib.c:390: warning: Excess function parameter
'deny' description in 'aa_check_perms'

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>