mmc: mtk-sd: receive cmd8 data when hs400 tuning fail

[ Upstream commit 9374ae912dbb1eed8139ed75fd2c0f1b30ca454d ]

When we use cmd8 as the tuning command in hs400 mode, the command
response sent back by some eMMC devices cannot be correctly sampled
by MTK eMMC controller at some weak sample timing. In this case,
command timeout error may occur. So we must receive the following
data to make sure the next cmd8 send correctly.

Signed-off-by: Mengqi Zhang <mengqi.zhang@mediatek.com>
Fixes: c4ac38c6

 ("mmc: mtk-sd: Add HS400 online tuning support")
Cc: stable@vger.stable.com
Link: https://lore.kernel.org/r/20240716013704.10578-1-mengqi.zhang@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>