nir/linker: fix msvc build

Empty initializer braces aren't valid c (it's a gnu extension, and
it's valid in c++).
Hopefully fixes appveyor / msvc build...

Fixes 6677e131b8
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>

src/compiler/glsl/gl_nir_link_atomics.c

@@ -175,7 +175,7 @@ gl_nir_link_assign_atomic_counter_resources(struct gl_context *ctx,
                                             struct gl_shader_program *prog)
 {
    unsigned num_buffers;
-   unsigned num_atomic_buffers[MESA_SHADER_STAGES] = { };
+   unsigned num_atomic_buffers[MESA_SHADER_STAGES] = {0};
    struct active_atomic_buffer *abs =
       find_active_atomic_counters(ctx, prog, &num_buffers);