You have to rebuild dpdk into rootfs in LSDK 21.08.
flex-builder -c openssl -a arm64 # to resolve the dependency on OpenSSL package
flex-builder -c linux -a arm64 # to resolve the dependency of KNI module
flex-builder -c dpdk -a arm64 # build dpdk application
flex-builder -c pktgen_dpdk -a arm64 # to generate dpdk pktgen application
flex-builder -c ovs_dpdk # to generate ovs-dpdk binaries
flex-builder -i merge-component -a arm64
flex-builder -i packrfs -r ubuntu:main