dracut: 90kernel-modules/module-setup.sh: add ehci-tegra.ko on arm

kernel-tegra is now part of the base kernel package, so bits and pieces
ended up modular, and as a result, if you boot off the internal USB, you
drop to a dracut shell with no way of getting to root.

modules.d/90kernel-modules/module-setup.sh

@@ -47,7 +47,8 @@ installkernel() {
         if [[ "$(uname -p)" == arm* ]]; then
             # arm specific modules
             hostonly='' instmods sdhci_esdhc_imx mmci sdhci_tegra mvsdio omap omapdrm \
-                omap_hsmmc panel-tfp410 sdhci_dove ahci_platform pata_imx sata_mv
+                omap_hsmmc panel-tfp410 sdhci_dove ahci_platform pata_imx sata_mv \
+                ehci-tegra
         fi
 
         # install virtual machine support