x86/hypercall: enable the test on non-KVM environment

KVM knows to emulate both vmcall and vmmcall regardless of the
actual architecture. Native hardware does not behave this way. Based on
the availability of test-device, figure out that the test is run on
non-KVM environment, and if so, run vmcall/vmmcall based on the actual
architecture.

Signed-off-by: Nadav Amit <nadav.amit@gmail.com>
Message-Id: <20210609182945.36849-5-nadav.amit@gmail.com>