pmdomain: arm: Add print after a successful probe for SCMI power domains

pmdomain: arm: Add print after a successful probe for SCMI power domains

It can be discussed how useful a print is after a successful probe. In the
SCMI power domain case it's seems valuable, as it let us inform about the
number of initialized power domains too, which is fetched from firmware.

Therefore, let's add a print about this, which also aligns with the
behaviour of the SCMI perf domain driver.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@kernel.org>