Reland: Use "gfxstream" namespace

This reverts commit 5d733516cbc2d636c716fe0f24ad05cfbef80855.

Reland adds in aosp/2514000 which was only built on the "full"
target.

Bug: b/271464937
Test: android build
Test: cmake build
Change-Id: I480285e32d44f27bcc8068d3e010c7f10c4bfabe
4 files changed