drm_hwcomposer: Move rotation enum querying into DrmPlane initialization

Benefits:
1. Improve readability.
2. Less logic in runtime slightly reduces overhead on CPU.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/drm/DrmPlane.h b/drm/DrmPlane.h
index 5782532..89523a6 100644
--- a/drm/DrmPlane.h
+++ b/drm/DrmPlane.h
@@ -84,6 +84,7 @@
   std::map<DrmHwcBlending, uint64_t> blending_enum_map_;
   std::map<DrmHwcColorSpace, uint64_t> color_encoding_enum_map_;
   std::map<DrmHwcSampleRange, uint64_t> color_range_enum_map_;
+  std::map<DrmHwcTransform, uint64_t> transform_enum_map_;
 };
 }  // namespace android