Some hypercalls return -ENODEV which should be set into RAX as return
value, e.g. HC_ASSIGN_PCIDEV. So, remove the check in
vmcall_vmexit_handler() and change return value to -EACCESS if the
hypercall is not sent from Service VM or allowed VM.
Tracked-On: #8598
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>