Add kvm_set_ioeventfd_mmio_long definition for non-KVM systems

Signed-off-by: Cam Macdonell <cam@cs.ualberta.ca>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

kvm-stub.c

@@ -136,3 +136,8 @@ int kvm_set_ioeventfd_pio_word(int fd, uint16_t addr, uint16_t val, bool assign)
 {
     return -ENOSYS;
 }
+
+int kvm_set_ioeventfd_mmio_long(int fd, uint32_t adr, uint32_t val, bool assign)
+{
+    return -ENOSYS;
+}