mmc: renesas_sdhi: only reset SCC when its pointer is populated

stable inclusion
from stable-v5.10.198
commit 1e3d016a95067ab3e6fcd245ba67b644a6b7d698
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I987V5

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1e3d016a95067ab3e6fcd245ba67b644a6b7d698



--------------------------------

commit 45bffc37 upstream.

Only re-initialize SCC and tuning when an SCC was found during probe().
This is currently a noop because all R-Car Gen2+ are considered to have
an SCC. But this will change in a later patch, so we need this
preparation.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20201110142058.36393-2-wsa+renesas@sang-engineering.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>