ARM: tegra: acer-a500: Correct PINCTRL configuration

The low-power-mode drive was set to DIV_4 for some of PINCTRL groups,
while these groups should use DIV_1. This patch fixes the wrong PINCTRL
configurations and adds a full drive-setup for the changed configs, just
for completeness since the added values match the default configuration.

Now WiFi SDIO communication works properly using legacy signaling mode if
SDIO BUS clocked at 50MHz, which is a maximum SDIO clock rate on Tegra20.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>