soc: qcom: rpmhpd: Use corner in power_off

rpmhpd_aggregate_corner() takes a corner as parameter, but in
rpmhpd_power_off() the code requests the level of the first corner
instead.

In all (known) current cases the first corner has level 0, so this
change should be a nop, but in case that there's a power domain with a
non-zero lowest level this makes sure that rpmhpd_power_off() actually
requests the lowest level - which is the closest to "power off" we can
get.

While touching the code, also skip the unnecessary zero-initialization
of "ret".

Fixes: 279b7e8a ("soc: qcom: rpmhpd: Add RPMh power domain driver")
Reviewed-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
Tested-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20210703005416.2668319-2-bjorn.andersson@linaro.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>