Do not use AIDL Dataspace in Color.cpp

Instead this uses the "HAL_DATASPACE" version of DISPLAY_BT2020 which is
available on all platforms and avoids the need to add custom code for
host builds.

Flag: com.android.graphics.flags.display_bt2020_colorspace
Bug: 74062470
Test: m libhwui on host
Change-Id: I664992395ab1d9985b4fbe0867f1535503868e4c