dpdk: enable -mavx/-mavx2 if available
dpdk: enable -mavx/-mavx2 if available

To support HEAD version of DPDK, we need -mavx/-mavx2 on Seastar CFLAGS.
But we cannot enable it until Host CPU has the feature, so we need to check it.

Signed-off-by: Takuya ASADA <4ebfb6f510af412d6e89fefa3ab96d9c8b5e3fff@cloudius-systems.com>

kjniemi/scylla,respu/scylla,shyamalschandra/seastar,shaunstanislaus/scylla,scylladb/seastar,flashbuckets/seastar,jonathanleang/seastar,rentongzhang/scylla,kjniemi/scylla,bowlofstew/seastar,joerg84/seastar,scylladb/seastar,dwdm/scylla,wildinto/scylla,tempbottle/seastar,scylladb/scylla-seastar,rluta/scylla,bzero/seastar,xtao/seastar,stamhe/seastar,anzihenry/seastar,syuu1228/seastar,duarten/scylla,eklitzke/scylla,dwdm/scylla,xtao/seastar,printedheart/seastar,victorbriz/scylla,victorbriz/scylla,avikivity/scylla,respu/scylla,bowlofstew/scylla,scylladb/scylla,tempbottle/scylla,mixja/seastar,capturePointer/scylla,senseb/scylla,guiquanz/scylla,raphaelsc/scylla,phonkee/scylla,norcimo5/seastar,dwdm/seastar,justintung/scylla,linearregression/scylla,koolhazz/seastar,duarten/scylla,capturePointer/scylla,dreamsxin/seastar,kangkot/scylla,kjniemi/seastar,glommer/scylla,gwicke/scylla,leejir/seastar,gwicke/scylla,acbellini/scylla,acbellini/seastar,aruanruan/scylla,hongliangzhao/seastar,printedheart/seastar,linearregression/seastar,kangkot/scylla,phonkee/scylla,shyamalschandra/seastar,bzero/seastar,dwdm/scylla,senseb/scylla,kangkot/scylla,mixja/seastar,linearregression/seastar,shaunstanislaus/scylla,acbellini/scylla,kjniemi/seastar,anzihenry/seastar,dreamsxin/seastar,chunshengster/seastar,shyamalschandra/seastar,acbellini/seastar,koolhazz/seastar,tempbottle/scylla,linearregression/scylla,respu/scylla,stamhe/seastar,sjperkins/seastar,norcimo5/seastar,syuu1228/seastar,rentongzhang/scylla,justintung/scylla,ducthangho/imdb,avikivity/seastar,leejir/seastar,sjperkins/seastar,chunshengster/seastar,rluta/scylla,hongliangzhao/seastar,norcimo5/seastar,mixja/seastar,scylladb/scylla,joerg84/seastar,stamhe/scylla,bowlofstew/scylla,avikivity/scylla,bowlofstew/scylla,chunshengster/seastar,wildinto/scylla,stamhe/scylla,asias/scylla,koolhazz/seastar,wildinto/scylla,eklitzke/scylla,linearregression/scylla,printedheart/seastar,capturePointer/scylla,shaunstanislaus/scylla,hongliangzhao/seastar,rluta/scylla,jonathanleang/seastar,dreamsxin/seastar,scylladb/scylla,ducthangho/imdb,raphaelsc/scylla,scylladb/scylla,asias/scylla,dwdm/seastar,kjniemi/scylla,flashbuckets/seastar,stamhe/seastar,victorbriz/scylla,flashbuckets/seastar,raphaelsc/scylla,stamhe/scylla,glommer/scylla,tempbottle/scylla,bowlofstew/seastar,rentongzhang/scylla,kjniemi/seastar,bzero/seastar,scylladb/scylla-seastar,avikivity/seastar,senseb/scylla,guiquanz/scylla,tempbottle/seastar,guiquanz/scylla,bowlofstew/seastar,jonathanleang/seastar,anzihenry/seastar,syuu1228/seastar,wildinto/seastar,cloudius-systems/seastar,phonkee/scylla,cloudius-systems/seastar,xtao/seastar,duarten/scylla,gwicke/scylla,scylladb/seastar,leejir/seastar,ducthangho/imdb,wildinto/seastar,linearregression/seastar,dwdm/seastar,sjperkins/seastar,justintung/scylla,aruanruan/scylla,wildinto/seastar,cloudius-systems/seastar,eklitzke/scylla,scylladb/scylla-seastar,avikivity/seastar,aruanruan/scylla,acbellini/scylla,glommer/scylla,tempbottle/seastar,asias/scylla,acbellini/seastar,avikivity/scylla,joerg84/seastar