drm_hwcomposer: Move include/drmhwcgralloc.h to bufferinfo/BufferInfo.h

... to emphasize its purpose.

- Rename struct HwcDrmBo -> struct BufferInfo
- Remove unused BufferInfo::acquire_fence, BufferInfo::hal_format and
  BufferInfo::usage fields

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/bufferinfo/legacy/BufferInfoImagination.h b/bufferinfo/legacy/BufferInfoImagination.h
index 765b279..4066d11 100644
--- a/bufferinfo/legacy/BufferInfoImagination.h
+++ b/bufferinfo/legacy/BufferInfoImagination.h
@@ -27,7 +27,7 @@
  public:
   using LegacyBufferInfoGetter::LegacyBufferInfoGetter;
 
-  int ConvertBoInfo(buffer_handle_t handle, hwc_drm_bo_t *bo) override;
+  int ConvertBoInfo(buffer_handle_t handle, BufferInfo *bo) override;
 };
 }  // namespace android