mmc: sdhci-of-at91: remove bogus MMC_SDHCI_IO_ACCESSORS select

I see no override of read/write callbacks in sdhci-of-at91.c.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Kconfig

@@ -135,7 +135,6 @@ config MMC_SDHCI_OF_AT91
 	tristate "SDHCI OF support for the Atmel SDMMC controller"
 	depends on MMC_SDHCI_PLTFM
 	depends on OF
-	select MMC_SDHCI_IO_ACCESSORS
 	help
 	  This selects the Atmel SDMMC driver