SurfaceFlinger: handle properly layers with Max refresh rate

Fix a bug where layers that voted LayerVoteType::Max are ignored if there are
other layers with a numerical vote.

Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Bug: 147516364
Change-Id: I177ebbd9fa31544997216d951fe697f06670e0a4
3 files changed