mmc: sdhci-pci: Set MMC_CAP_CMD_DURING_TFR for Intel eMMC controllers

Set MMC_CAP_CMD_DURING_TFR for Intel BYT and related eMMC host controllers.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>