drm_hwcomposer: Use linear scaling instead of nearest neighbor

So scaled layer transitions between hw plane and gl plane look better.

BUG=b/28431632
TEST=Tested on low resolution paused YouTube video

Change-Id: I507722c28c5b8ec4e8d16ae436a04afc8cffaa0f
Signed-off-by: Sean Paul <seanpaul@chromium.org>
diff --git a/glworker.cpp b/glworker.cpp
index 7f154aa..6ce2de3 100644
--- a/glworker.cpp
+++ b/glworker.cpp
@@ -430,8 +430,8 @@
   glGenTextures(1, &texture);
   glBindTexture(GL_TEXTURE_EXTERNAL_OES, texture);
   glEGLImageTargetTexture2DOES(GL_TEXTURE_EXTERNAL_OES, (GLeglImageOES)image);
-  glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-  glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_WRAP_S, GL_REPEAT);
   glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GL_TEXTURE_WRAP_T, GL_REPEAT);
   glBindTexture(GL_TEXTURE_EXTERNAL_OES, 0);