should be CONFIG_EXAMPLES_PTYTEST_SERIALDEV, regression in commit:
commit 6ddbffd2000fb62c71914c6f57c93f2e7d1f50e8
Author: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Sun Jan 3 23:50:50 2021 -0800
examples/pty_test: Remove O_NONBLOCK from open
to avoid the log storm:
ERROR Failed to read from serial: 11
ERROR Failed to read from serial: 11
ERROR Failed to read from serial: 11
ERROR Failed to read from serial: 11
ERROR Failed to read from serial: 11
...
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>