platform/x86: lenovo-yoga-tab2-pro-1380-fastcharger: fix serdev race

The yt2_1380_fc_serdev_probe() function calls devm_serdev_device_open()
before setting the client ops via serdev_device_set_client_ops(). This
ordering can trigger a NULL pointer dereference in the serdev controller's
receive_buf handler, as it assumes serdev->ops is valid when
SERPORT_ACTIVE is set.

This is similar to the issue fixed in commit 5e700b38
("platform/chrome: cros_ec_uart: properly fix race condition") where
devm_serdev_device_open() was called before fully initializing the
device.

Fix the race by ensuring client ops are set before enabling the port via
devm_serdev_device_open().

Note, serdev_device_set_baudrate() and serdev_device_set_flow_control()
calls should be after the devm_serdev_device_open() call.

Fixes: b2ed33e8 ("platform/x86: Add lenovo-yoga-tab2-pro-1380-fastcharger driver")
Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20250111180951.2277757-1-chenyuan0y@gmail.com


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>