Revert "Reland: Use "gfxstream" namespace"

Revert submission 2513870-gfxstream-namespace-2

Reason for revert: This breaks the MacOS gfxstream build.

Reverted changes: /q/submissionid:2513870-gfxstream-namespace-2
Bug: 276321260

Change-Id: I9452eef98ae938d713972dc495bdc56c862e1e0e
4 files changed