PTP_KVM support for arm/arm64

PTP_KVM is used for high precision time sync between host and guests. It relies on transferring the wall clock and counter value from the host to the guest using a KVM-specific hypercall.

• ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: 0x86000001

This hypercall uses the SMC32/HVC32 calling convention:

ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID