soc: qcom: rpmh: Update rpmh_invalidate function to return void

Currently rpmh_invalidate() always returns success. Update its
return type to void.

Reviewed-by: Lina Iyer <ilina@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Suggested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
Link: https://lore.kernel.org/r/1592485553-29163-1-git-send-email-mkshah@codeaurora.org


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