mmc: dt: Consolidate DT bindings

This patch unifies the current DT MMC bindings documentation and code,
adds generic MMC DT bindings documentation, and updates .dts files for
consistency.

[cjb: typo fixes, addition of max-frequency property]
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/arm/boot/dts/tegra-paz00.dts b/arch/arm/boot/dts/tegra-paz00.dts
index 6c02abb..03d3d79 100644
--- a/arch/arm/boot/dts/tegra-paz00.dts
+++ b/arch/arm/boot/dts/tegra-paz00.dts
@@ -97,6 +97,7 @@
 		cd-gpios = <&gpio 173 0>; /* gpio PV5 */
 		wp-gpios = <&gpio 57 0>;  /* gpio PH1 */
 		power-gpios = <&gpio 169 0>; /* gpio PV1 */
+		bus-width = <4>;
 	};
 
 	sdhci@c8000200 {
@@ -109,6 +110,7 @@
 
 	sdhci@c8000600 {
 		support-8bit;
+		bus-width = <8>;
 	};
 
 	gpio-keys {