gallium: Add the ASTC 3D formats.

No driver implements them yet, but this is a long way toward gallium
having matching format enums for Mesa formats.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
22 jobs for !1698 with gallium-astc-3d in 38 minutes and 41 seconds (queued for 58 seconds)
detached
Status Name Job ID Coverage
  Containers Build
passed debian #536479

00:00:19

 
  Build+Test
passed meson-arm64 #536488

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passed meson-armhf #536487

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passed meson-clang #536481

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passed meson-clover #536485

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passed meson-i386 #536489

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passed meson-main #536484

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passed meson-swr-glvnd #536480

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passed meson-vulkan #536486

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passed scons-llvm #536491

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passed scons-nollvm #536490

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passed scons-swr #536482

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passed scons-win64 #536483

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  Test
passed test-llvmpipe-gles2 1/4 #536492

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passed test-llvmpipe-gles2 2/4 #536493

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passed test-llvmpipe-gles2 3/4 #536494

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passed test-llvmpipe-gles2 4/4 #536495

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passed test-softpipe-gles2 1/4 #536496

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passed test-softpipe-gles2 2/4 #536497

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passed test-softpipe-gles2 3/4 #536498

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passed test-softpipe-gles2 4/4 #536499

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passed test-softpipe-gles3-limited #536500

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