Coverity reported that an argument for sizeof was used improperly.
We should allocate memory for value size that pointer points to,
instead of pointer size itself.
Coverity issue: 144522
Fixes: 79c913a42f0e ("ethdev: retrieve xstats by ID")
Signed-off-by: Michal Jastrzebski <michalx.k.jastrzebski@intel.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>