mmc: Kconfig: Enable CONFIG_MMC_SDHCI_IO_ACCESSORS

commit 99d570da309813f67e9c741edeff55bafc6c1d5e upstream.

Enable CONFIG_MMC_SDHCI_IO_ACCESSORS so that SDHC controller specific
register read and write APIs, if registered, can be used.

Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Koen Vandeputte <koen.vandeputte@ncentric.com>
Cc: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>