This reverts commit 923b2e30.

This is not a correct fix as TCA_EXT_WARN_MSG is not a hierarchy to
TCA_ACT_TAB. I didn't notice the TC actions use different enum when adding
TCA_EXT_WARN_MSG. To fix the difference I will add a new WARN enum in
TCA_ROOT_MAX as Jamal suggested.
Signed-off-by: NHangbin Liu <liuhangbin@gmail.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>