Build of test_compressdev.c fails on FreeBSD due to the missing
include of unistd.h, to provide the function usleep.
Fixes: b06aa643cac4 ("test/compress: add initial unit tests")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>