clocksource/drivers/timer-ti-dm: Improve error message in .remove

If a platform driver's remove callback returns an error code, the driver
core emits a generic (and thus little helpful) error message.

Instead emit a more specifc error message about the actual error and
return zero to suppress the core's message.

Note that returning zero has no side effects apart from not emitting
said error message. This prepares converting platform driver's remove
message to return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230313075430.2730803-4-u.kleine-koenig@pengutronix.de