[ Upstream commit fc02e2b52389c8fde02852b2f959c0b45f042bbd ] Let's use pr_err() to output the error messages and let's extend a comment to clarify why returning 0 (success) in one case make sense. Fixes: c784f92769ae ("mmc: core: Read the SD function extension registers for power management") Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> [Ulf: Clarified the comment and the commit-msg] Link: https://lore.kernel.org/r/20221130134920.2109-1-thunder.leizhen@huawei.com Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>