[ELSA-2018-4126] Unbreakable Enterprise kernel security update

[4.1.12-124.15.4]
- x86/bugs/IBRS: Keep SSBD mitigation in effect if spectre_v2=ibrs is selected (Mihai Carabas)

- fs/pstore: update the backend parameter in pstore module (Wang Long) [Orabug: 27994372]
- kvm: vmx: Reinstate support for CPUs without virtual NMI (Paolo Bonzini) [Orabug: 28041210]
- dm crypt: add big-endian variant of plain64 IV (Milan Broz) [Orabug: 28043932]
- x86/bugs: Rename SSBD_NO to SSB_NO (Konrad Rzeszutek Wilk) [Orabug: 28063992] {CVE-2018-3639}
- KVM: SVM: Implement VIRT_SPEC_CTRL support for SSBD (Tom Lendacky) [Orabug: 28063992] [Orabug: 28069548] {CVE-2018-3639}
- x86/speculation, KVM: Implement support for VIRT_SPEC_CTRL/LS_CFG (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/bugs: Rework spec_ctrl base and mask logic (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/bugs: Expose x86_spec_ctrl_base directly (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/bugs: Unify x86_spec_ctrl_{set_guest,restore_host} (Borislav Petkov) [Orabug: 28063992] {CVE-2018-3639}
- x86/speculation: Rework speculative_store_bypass_update() (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/speculation: Add virtualized speculative store bypass disable support (Tom Lendacky) [Orabug: 28063992] {CVE-2018-3639}
- x86/bugs, KVM: Extend speculation control for VIRT_SPEC_CTRL (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/speculation: Handle HT correctly on AMD (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/cpufeatures: Add FEATURE_ZEN (Thomas Gleixner) [Orabug: 28063992] {CVE-2018-3639}
- x86/cpu/AMD: Fix erratum 1076 (CPB bit) (Borislav Petkov) [Orabug: 28063992] {CVE-2018-3639}

[4.1.12-124.15.3]
- perf/hwbp: Simplify the perf-hwbp code, fix documentation (Linus Torvalds) [Orabug: 27947602] {CVE-2018-1000199}
- Revert 'perf/hwbp: Simplify the perf-hwbp code, fix documentation' (Brian Maly) [Orabug: 27947602]