drm_hwcomposer: Tidy-up DrmPlane class

This allow to throw away few lines from DrmDevice::Init() making it less
complicated.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/hwc2_device/DrmHwcTwo.cpp b/hwc2_device/DrmHwcTwo.cpp
index a2a093f..87cc238 100644
--- a/hwc2_device/DrmHwcTwo.cpp
+++ b/hwc2_device/DrmHwcTwo.cpp
@@ -43,7 +43,7 @@
   }
   auto display_planes = std::vector<DrmPlane *>();
   for (const auto &plane : drm->planes()) {
-    if (plane->GetCrtcSupported(*crtc))
+    if (plane->IsCrtcSupported(*crtc))
       display_planes.push_back(plane.get());
   }
   displays_.at(displ).Init(&display_planes);