Broadcom BCM281xx SDHCI

This file documents differences between the core properties in mmc.txt
and the properties present in the bcm281xx SDHCI

Required properties:
- compatible : Should be "bcm,kona-sdhci"

Example:

sdio2: sdio@0x3f1a0000 {
        compatible = "bcm,kona-sdhci";
        reg = <0x3f1a0000 0x10000>;
        interrupts = <0x0 74 0x4>;
};