composer: 2.4: VTS using old value for parameter

Fix a test that is using the incorrect parameter.

Bug: 161023185
Test: adb shell data/nativetest64/VtsHalGraphicsComposerV2_4TargetTest/VtsHalGraphicsComposerV2_4TargetTest
Change-Id: I8574abed50c23657f5d96e9d396709cb9b92e1fd