KVM: arm64: Add vendor hypervisor firmware register

KVM: arm64: Add vendor hypervisor firmware register

Introduce the firmware register to hold the vendor specific
hypervisor service calls (owner value 6) as a bitmap. The
bitmap represents the features that'll be enabled for the
guest, as configured by the user-space. Currently, this
includes support for KVM-vendor features along with
reading the UID, represented by bit-0, and Precision Time
Protocol (PTP), represented by bit-1.

Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Reviewed-by: Gavin Shan <[email protected]>
[maz: tidy-up bitmap values]
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]