mem: fix allocation failure on non-NUMA kernel

mem: fix allocation failure on non-NUMA kernel

Running dpdk-helloworld on Linux with lib numa present, but no kernel
support for NUMA (CONFIG_NUMA=n) causes rte_service_init() to fail with
EAL: error allocating rte services array.

alloc_seg() calls get_mempolicy to verify that the allocation
has happened on the correct socket, but receives ENOSYS from
the kernel and fails the allocation.

The allocated socket should only be verified if check_numa() is true.

Fixes: 2a96c88be83e ("mem: ease init in a docker container")
Cc: stable@dpdk.org
Signed-off-by: Nick Connolly <nick.connolly@mayadata.io>
Reviewed-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>