Test soc path for modalias needed by drm

On ARM, both pci and soc path can be tested for drm.

With this patchset, that was missing in recent kernel,
the tegra_drm case is not needed anymore:
http://patchwork.ozlabs.org/patch/361765/
http://www.spinics.net/lists/linux-tegra/msg17948.html

modules.d/50drm/module-setup.sh

@@ -57,7 +57,7 @@ installkernel() {
         # as we could e.g. be in the installer; nokmsboot boot parameter will disable
         # loading of the driver if needed
         if [[ $hostonly ]] && modinfo -F alias $_modname | sed -e 's,\?,\.,g' -e 's,\*,\.\*,g' \
-            | grep -qxf - /sys/bus/pci/devices/*/modalias 2>/dev/null; then
+            | grep -qxf - /sys/bus/{pci/devices,soc/devices/soc?}/*/modalias 2>/dev/null; then
             hostonly='' instmods $_modname
             continue
         fi