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/omap3-beagle.dts b/arch/arm/boot/dts/omap3-beagle.dts
index 8c756be..5b4506c 100644
--- a/arch/arm/boot/dts/omap3-beagle.dts
+++ b/arch/arm/boot/dts/omap3-beagle.dts
@@ -57,7 +57,7 @@
 &mmc1 {
 	vmmc-supply = <&vmmc1>;
 	vmmc_aux-supply = <&vsim>;
-	ti,bus-width = <8>;
+	bus-width = <8>;
 };
 
 &mmc2 {