LF-4086-2 mmc: sdhci-esdhc-imx: Add documentation for fsl,sdio-interrupt-enabled property

uSDHC controller can enable auto tuning for DAT[0] and CMD only. Add
documentation for fsl,sdio-interrupt-enabled device tree property.

Signed-off-by: Breno Lima <breno.lima@nxp.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>