ARM: tegra: colibri: Replace eMMC label by comment

Rather than a bogus label just add a comment identifying the SDHCI
instance connected to the on-module eMMC.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra30-colibri.dtsi

@@ -396,7 +396,8 @@ pmc@7000e400 {
 		nvidia,sys-clock-req-active-high;
 	};
 
-	emmc: sdhci@78000600 {
+	/* eMMC */
+	sdhci@78000600 {
 		status = "okay";
 		bus-width = <8>;
 		non-removable;