Merge branch kvm-arm64/ffa-1.2 into kvmarm-master/next

* kvm-arm64/ffa-1.2:
  : .
  : FFA 1.2 support for pKVM, courtesy of Per Larsen.
  :
  : From the cover letter at [1]:
  :
  : "The FF-A 1.2 specification introduces a new SEND_DIRECT2 ABI which
  :  allows registers x4-x17 to be used for the message payload. This patch
  :  set prevents the host from using a lower FF-A version than what has
  :  already been negotiated with the hypervisor. This is necessary because
  :  the hypervisor does not have the necessary compatibility paths to
  :  translate from the hypervisor FF-A version to a previous version."
  :
  : [1] https://lore.kernel.org/r/20250820-virtio-msg-ffa-v11-0-497ef43550a3@google.com
  : .
  KVM: arm64: Bump the supported version of FF-A to 1.2
  KVM: arm64: Mask response to FFA_FEATURE call
  KVM: arm64: Mark optional FF-A 1.2 interfaces as unsupported
  KVM: arm64: Mark FFA_NOTIFICATION_* calls as unsupported
  KVM: arm64: Use SMCCC 1.2 for FF-A initialization and in host handler
  KVM: arm64: Correct return value on host version downgrade attempt

Signed-off-by: Marc Zyngier <maz@kernel.org>