drm_hwcomposer: Move IsKMSDev to DrmDevice

IsKMSDev() is a DRM device helper, therefore DrmDevice class
is better home for it.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/drm/ResourceManager.cpp b/drm/ResourceManager.cpp
index 5a5a241..c55d6b8 100644
--- a/drm/ResourceManager.cpp
+++ b/drm/ResourceManager.cpp
@@ -51,7 +51,7 @@
       if (stat(path.str().c_str(), &buf))
         break;
 
-      if (IsKMSDev(path.str().c_str()))
+      if (DrmDevice::IsKMSDev(path.str().c_str()))
         ret = AddDrmDevice(path.str());
     }
   }
@@ -83,23 +83,6 @@
   return ret;
 }
 
-bool ResourceManager::IsKMSDev(const char *path) {
-  auto fd = UniqueFd(open(path, O_RDWR | O_CLOEXEC));
-  if (!fd) {
-    return false;
-  }
-
-  auto res = MakeDrmModeResUnique(fd.Get());
-  if (!res) {
-    return false;
-  }
-
-  bool is_kms = res->count_crtcs > 0 && res->count_connectors > 0 &&
-                res->count_encoders > 0;
-
-  return is_kms;
-}
-
 DrmDevice *ResourceManager::GetDrmDevice(int display) {
   for (auto &drm : drms_) {
     if (drm->HandlesDisplay(display))