mmc: sdhci-acpi: Reduce Baytrail eMMC/SD/SDIO hangs

mmc: sdhci-acpi: Reduce Baytrail eMMC/SD/SDIO hangs

Baytrail eMMC/SD/SDIO host controllers have been known to
hang.  A change to a hardware setting has been found to
reduce the occurrence of such hangs.  This patch ensures
the correct setting.

This patch applies cleanly to v4.4+.  It could go to
earlier kernels also, so I will send backports to the
stable list in due course.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>