drm_hwcomposer: Rename DrmResources to DrmDevice

DrmDevice is a better name to reflect the fact that DrmResources/
DrmDevice can handle just one dri node.

Suggested here [1] by Sean Paul.
[1] https://lists.freedesktop.org/archives/dri-devel/2018-April/173290.html

Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
diff --git a/drmplane.h b/drmplane.h
index 5b73b08..a293afe 100644
--- a/drmplane.h
+++ b/drmplane.h
@@ -26,11 +26,11 @@
 
 namespace android {
 
-class DrmResources;
+class DrmDevice;
 
 class DrmPlane {
  public:
-  DrmPlane(DrmResources *drm, drmModePlanePtr p);
+  DrmPlane(DrmDevice *drm, drmModePlanePtr p);
   DrmPlane(const DrmPlane &) = delete;
   DrmPlane &operator=(const DrmPlane &) = delete;
 
@@ -57,7 +57,7 @@
   const DrmProperty &in_fence_fd_property() const;
 
  private:
-  DrmResources *drm_;
+  DrmDevice *drm_;
   uint32_t id_;
 
   uint32_t possible_crtc_mask_;