mmc: renesas_sdhi: Deassert the reset signal on probe

mmc: renesas_sdhi: Deassert the reset signal on probe

Deassert the reset signal of the SDHI controller during probe to avoid
relying on the previous bootloaders. Without deasserting the reset signal,
the SDHI controller will not function.

Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>