repo: Pin meta-seco-rockchip

Relate-to: #4
Relate-to: eclipse/oniro-core/oniro#156
Relate-to: eclipse/oniro-core/oniro#159
Relate-to: eclipse/oniro-core/oniro#542 (comment 876941)
Relate-to: eclipse/oniro-core/oniro#158


Signed-off-by: Philippe Coval <philippe.coval.ext@huawei.com>