fsi: scom: Fix NULL dereference

The chardev conversion forgot to copy the fsi_dev,
silly mistake, compounded by a testing mistake on
my side, this specific driver wasn't being tested
properly.

Fixes: d8f45876 "fsi: scom: Convert to use the new chardev"
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/fsi/fsi-scom.c

@@ -598,6 +598,7 @@ static int scom_probe(struct device *dev)
 		kfree(scom);
 		return -ENODEV;
 	}
+	scom->fsi_dev = fsi_dev;
 
 	/* Create chardev for userspace access */
 	scom->dev.type = &fsi_cdev_type;