Fix compile error on arm64
On x86_64 and arm32, RTE_CACHE_LINE_SIZE is 64. On arm64 it's 128. Latsamp_status is an array of cache aligned values, so sizeof(latsamp_stats_t) needs to be divisible by 128 for pktgen to compile on arm64.
Signed-off-by: David Albert davidbalbert@gmail.com