mmc: sdhci-of-arasan: fix missing sdhci_pltfm_free for err handling

Currently, some err handling of sdhci_arasan_probe return directly
without calling sdhci_pltfm_free. This patch fixes them.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>