hw/virtio: Use error_setg_file_open() for a better error message

The error message changes from

    vhost-vsock: failed to open vhost device: REASON

to

    Could not open '/dev/vhost-vsock': REASON

I think the exact file name is more useful to know than the file's
purpose.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20251121121438.1249498-8-armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/virtio/vhost-vsock.c

@@ -153,8 +153,7 @@ static void vhost_vsock_device_realize(DeviceState *dev, Error **errp)
     } else {
         vhostfd = open("/dev/vhost-vsock", O_RDWR);
         if (vhostfd < 0) {
-            error_setg_errno(errp, errno,
-                             "vhost-vsock: failed to open vhost device");
+            error_setg_file_open(errp, errno, "/dev/vhost-vsock");
             return;
         }