mmc: sdhci-st: Obviously always return success in remove callback

sdhci_pltfm_unregister() returns 0 unconditionally and returning an
error in a platform remove callback isn't very sensible. (The only
effect of the latter is that the device core emits a generic warning and
then removes the device anyhow.)

So return 0 unconditionally to make it obvious there is no error
forwarded to the upper layers.

This is a preparation for making platform remove callbacks return void.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20220610211257.102071-5-u.kleine-koenig@pengutronix.deSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-st.c

@@ -440,15 +440,14 @@ static int sdhci_st_remove(struct platform_device *pdev)
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct st_mmc_platform_data *pdata = sdhci_pltfm_priv(pltfm_host);
 	struct reset_control *rstc = pdata->rstc;
-	int ret;
 
-	ret = sdhci_pltfm_unregister(pdev);
+	sdhci_pltfm_unregister(pdev);
 
 	clk_disable_unprepare(pdata->icnclk);
 
 	reset_control_assert(rstc);
 
-	return ret;
+	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP