Important: kernel security update (Oracle Linux 8)

[4.18.0-348.2.1_5.OL8]
- Update Oracle Linux certificates (Kevin Lyons)
- Disable signing for aarch64 (Ilya Okomin)
- Oracle Linux RHCK Module Signing Key was added to the kernel trusted keys list (olkmod_signing_key.pem) [Orabug: 29539237]
- Update x509.genkey [Orabug: 24817676]
- Conflict with shim-ia32 and shim-x64 <= 15-11.0.5

[4.18.0-348.2.1_5]
- tipc: fix size validations for the MSG_CRYPTO type (Bruno Meneguele) [2020506 2020507] {CVE-2021-43267}
- net: Fix skb->csum update in inet_proto_csum_replace16(). (Balazs Nemeth) [2005981 1975193]

[4.18.0-348.1.1_5]
- lib/timerqueue: Rely on rbtree semantics for next timer (Phil Auld) [2014677 2007099] {CVE-2021-20317}
- mm/hmm: make HMM_MIRROR an implicit option (Rafael Aquini) [2017519 1998534]
- mm/hmm: allow HMM_MIRROR on all architectures with MMU (Rafael Aquini) [2017519 1998534]
- mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR (Rafael Aquini) [2017519 1998534]
- mm: sort out the DEVICE_PRIVATE Kconfig mess (Rafael Aquini) [2017519 1998534]
- ceph: skip existing superblocks that are blocklisted or shut down when mounting (Jeffrey Layton) [2017071 2011462]
- redhat: switch release to zstream (Bruno Meneguele)