serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()"

The 8250 driver no longer depends on @oops_in_progress and
will no longer violate the port->lock locking constraints.

This reverts commit 3d9e6f55.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>