Make sure the trace history that is exported via shared memory is always the same size, regardless of DPDK configuration. Also removes the necessity of including DPDK headers from spdk/trace.h (so we have to fix up other files to include what they use). Change-Id: I32f88921fd95c64a9d1f4ba768ae75e2ca5d91da Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>