Util_hint support for arm64

Util_hint is used for sharing the utilization value from the guest to the host.

• ARM_SMCCC_HYP_KVM_UTIL_HINT_FUNC_ID: 0x86000042

This hypercall using the SMC32/HVC32 calling convention:

ARM_SMCCC_HYP_KVM_UTIL_HINT_FUNC_ID