drm_hwcomposer: Add supported formats list to DrmPlane

There are some use-cases for checking formats supported by given
plane. drmModePlane already contains reqired data, so it simply could
be saved into DrmPlane, no need to query any additional stuff.

Signed-off-by: Roman Kovalivskyi <roman.kovalivskyi@globallogic.com>
diff --git a/drm/DrmPlane.h b/drm/DrmPlane.h
index d2f0601..16731a8 100644
--- a/drm/DrmPlane.h
+++ b/drm/DrmPlane.h
@@ -43,6 +43,8 @@
 
   uint32_t type() const;
 
+  bool IsFormatSupported(uint32_t format) const;
+
   const DrmProperty &crtc_property() const;
   const DrmProperty &fb_property() const;
   const DrmProperty &crtc_x_property() const;
@@ -67,6 +69,8 @@
 
   uint32_t type_;
 
+  std::vector<uint32_t> formats_;
+
   DrmProperty crtc_property_;
   DrmProperty fb_property_;
   DrmProperty crtc_x_property_;