KVM: x86: pass kvm_vcpu to kvm_read_guest_virt and kvm_write_guest_virt_system

KVM: x86: pass kvm_vcpu to kvm_read_guest_virt and kvm_write_guest_virt_system

BugLink: http://bugs.launchpad.net/bugs/1790188
commit ce14e868a54edeb2e30cb7a7b104a2fc4b9d76ca upstream.

Int the next patch the emulator's .read_std and .write_std callbacks will
grow another argument, which is not needed in kvm_read_guest_virt and
kvm_write_guest_virt_system's callers.  Since we have to make separate
functions, let's give the currently existing names a nicer interface, too.

Fixes: 129a72a0d3c8 ("KVM: x86: Introduce segmented_write_std", 2017-01-12)
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>