nir/builder: Don't use designated initializers
nir/builder: Don't use designated initializers

Designated initializers are not allowed in C++ (not even C++11).  Since
nir_lower_samplers is now using nir_builder, and nir_lower_samplers is in
C++, this breaks the build on some compilers.  Aparently, GCC 5 allows it
in some limited extent because mesa still builds on my system without this
patch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92052
Reviewed-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler