libva-utils 2.7.1

• meson: add missing samples
• sfcsample: drop unused Linux-only header
• autotools: drop libdrm dependency (only libva-drm is used)
• autotools: drop unused X11 dependencies
• Add 10/12bit RT format check
• test/createsurfaces: add some scoped traces
• test/streamable: add VAConfigAttrib and VASurfaceAttrib
• Modify output CS settings for Chroma siting on Linux
• Align libva attribute check
• Added displaying supported config attributes
• add the VP samples README