Add SPIR-V headers

Added SPIR-V headers from khronos SPIRV-Headers repository on
commit c0df742ec0b8178ad58c68cff3437ad4b6a06e26.
Older versions were not included (1.0, 1.1 and 1.2).

The headers are used by latest Mali Valhall drivers.

git clone https://github.com/KhronosGroup/SPIRV-Headers
mkdir -p spirv/unified1/
rsync -av --ignore-times --delete \
SPIRV-Headers/include/spirv/unified1/spirv.h* spirv/unified1/

BUG=b:151287016
TEST=cros_workon-asurada start opengles-headers
     emerge-asurada opengles-headers
     emerge-asurada mali-drivers-valhall

Change-Id: Ia7e36eecd7a939e0e7b96ca331719f187e9e572a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/khronos/+/2200876
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Ilja H. Friedel <ihf@chromium.org>
Reviewed-by: Kristian H. Kristensen <hoegsberg@chromium.org>
Tested-by: Fei Shao <fshao@chromium.org>
Commit-Queue: Nicolas Boichat <drinkcat@chromium.org>
26 files changed