test/eal: fix --socket-mem option

test/eal: fix --socket-mem option

eal flag autotest fails when multiple mem size flags are passed to
--socket-mem option irrespective of RTE_MAX_NUMA_NODES and the number of
available sockets on the test system.

Fixes: 45f1b6e8680a ("app: add new tests on eal flags")
Cc: stable@dpdk.org
Signed-off-by: Vamsi Attunuru <vattunuru@marvell.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Vamsi Attunuru <vattunuru@marvell.com>
Tested-by: Vamsi Attunuru <vattunuru@marvell.com>