mmc: mediatek: free the ext_csd when mmc_get_ext_csd success

If mmc_get_ext_csd success, the ext_csd are not freed.
Add the missing kfree() calls.
Signed-off-by: Wenbin Mei <wenbin.mei@mediatek.com>
Fixes: c4ac38c6 ("mmc: mtk-sd: Add HS400 online tuning support")
Link: https://lore.kernel.org/r/20211207075013.22911-1-wenbin.mei@mediatek.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mtk-sd.c

@@ -2291,8 +2291,10 @@ static int msdc_execute_hs400_tuning(struct mmc_host *mmc, struct mmc_card *card
 			sdr_set_field(host->base + PAD_DS_TUNE,
 				      PAD_DS_TUNE_DLY1, i);
 		ret = mmc_get_ext_csd(card, &ext_csd);
-		if (!ret)
+		if (!ret) {
 			result_dly1 |= (1 << i);
+			kfree(ext_csd);
+		}
 	}
 	host->hs400_tuning = false;