backport "x86: change default to spec_store_bypass_disable=prctl spectre_v2_user=prctl"

[Mahmoud Adam <mngyadam@xxxxxxxxxx>]

Hi,

commit 2f46993d83ff upstream.

Please backport this commit to the other stable kernels, since this
patch landed on 6.1 and We've seen 30% improvement with docker
containers running heavy cpu/mem tasks


-MNAdam