opal: Submit PSID reset command to R/W file descriptor.

The PSID reset erases the block device it's submitted to
succesfully.

By submitting the command to read-only fd previously
there were partition device nodes still visible in
the /dev directory because kernel does not trigger rescan
after OPAL2 PSID reset. Even though all the partition were
actually erased (including the partition table).

We workaround the issue by submitting the PSID reset
to R/W fd so that it triggers rescan event on close.

lib/luks2/hw_opal/hw_opal.c

@@ -790,7 +790,11 @@ int opal_factory_reset(struct crypt_device *cd,
 	if (password_len > OPAL_KEY_MAX)
 		return -EINVAL;
 
-	fd = device_open(cd, dev, O_RDONLY);
+	/*
+	 * Submit PSID reset on R/W file descriptor so it
+	 * triggers blkid rescan after we close it.
+	 */
+	fd = device_open(cd, dev, O_RDWR);
 	if (fd < 0)
 		return -EIO;