mmc: renesas_sdhi: enforce manual correction for Gen3

mmc: renesas_sdhi: enforce manual correction for Gen3

HW engineers say that automatic tap correction cannot be used for HS400
in all R-Car Gen3 SoCs. So, check for that SDHI variant and disable it
when HS400 is about to be enabled.

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20191217114034.13290-5-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>