soc: qcom: ramp_controller: Improve error message for failure in .remove()

When a platform_driver's .remove() callback returns an error, the driver
core emits

	remove callback returned a non-zero value. This will be ignored.

. Replace this by a more specific error message. Then convert to
.remove_new() which is equivalent to returning zero unconditionally in
.remove(). See commit 5c5a7680 ("platform: Provide a remove callback
that returns no value") for its rationale.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230415201848.3779001-1-u.kleine-koenig@pengutronix.de