dt-bindings: sdhci-omap: Add pinctrl bindings

Add pinctrl binding rquired to get the mux mode and IODelay
values from devicetree.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/sdhci-omap.txt

@@ -7,6 +7,11 @@ Required properties:
 	      Should be "ti,k2g-sdhci" for K2G
 - ti,hwmods: Must be "mmc<n>", <n> is controller instance starting 1
 	     (Not required for K2G).
+- pinctrl-names: Should be subset of "default", "hs", "sdr12", "sdr25", "sdr50",
+		 "ddr50-rev11", "sdr104-rev11", "ddr50", "sdr104",
+		 "ddr_1_8v-rev11", "ddr_1_8v" or "ddr_3_3v", "hs200_1_8v-rev11",
+		 "hs200_1_8v",
+- pinctrl-<n> : Pinctrl states as described in bindings/pinctrl/pinctrl-bindings.txt
 
 Example:
 	mmc1: mmc@4809c000 {