dpdk: move submodule to build rte_rcu library

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: Ie38573774612ac7ec7cf23367d3233124acd1a66
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4953


Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>