drm_hwcomposer: Make Planner class fully static

clang-tidy suggested to make all methods of Planner static,
since they don't use any instance members.

This makes creation of Planner instances unnecessary, therefore
remove all such cases.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/compositor/DrmDisplayCompositor.cpp b/compositor/DrmDisplayCompositor.cpp
index a26f2df..2c2ec65 100644
--- a/compositor/DrmDisplayCompositor.cpp
+++ b/compositor/DrmDisplayCompositor.cpp
@@ -49,7 +49,6 @@
     ALOGE("Could not find drmdevice for display");
     return -EINVAL;
   }
-  planner_ = Planner::CreateInstance(drm);
 
   initialized_ = true;
   return 0;
@@ -64,7 +63,7 @@
     return std::unique_ptr<DrmDisplayComposition>();
   }
 
-  return std::make_unique<DrmDisplayComposition>(crtc, planner_.get());
+  return std::make_unique<DrmDisplayComposition>(crtc);
 }
 
 // NOLINTNEXTLINE (readability-function-cognitive-complexity): Fixme