intel/compiler: Fix non-trivial designated initializer

intel/compiler: Fix non-trivial designated initializer

Not supported by GCC 7.

src/compiler/nir/nir_builder_opcodes.h:14156:118:
sorry, unimplemented: non-trivial designated initializers not supported
src/intel/compiler/brw_mesh.cpp:515:7:
note: in expansion of macro ‘nir_store_per_primitive_output’

Reviewed-by: Marcin Ślusarz <marcin.slusarz@intel.com>
Fixes: bc4f8c073a2 ("intel/compiler: inject MUE initialization")
Signed-off-by: Ernst Sjöstrand <ernstp@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15360>