TESTS: read12/read16 change signature to return an optional task structure

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>

test-tool/test_writesame16_unmap_until_end.c

@@ -75,7 +75,7 @@ test_writesame16_unmap_until_end(void)
 
 			logging(LOG_VERBOSE, "Read %d blocks and verify they "
 				"are now zero", i);
-			ret = read16(sd, num_blocks - i,
+			ret = read16(sd, NULL, num_blocks - i,
 				     i * block_size, block_size,
 				     0, 0, 0, 0, 0, buf,
 				     EXPECT_STATUS_GOOD);