Add definitions for GetVpRegister and SetVpRegister hypercalls, which are implemented for both x86 and ARM64. Signed-off-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20200422195737.10223-5-mikelley@microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>