nv50/ir/nir: don't use designated initializers

This is a C++20 feature...

Fixes: 8850a63161ab58d89c534a1069cda845bf69ecc8 ("radv/aco,nir/lower_subgroups: don't lower elect")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/3693
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Tested-by: Andrew Randrianasulu <randrianasulu@gmail.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7338>
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp
index b256121..dca45e7 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp
@@ -3111,11 +3111,10 @@
    if (prog->dbgFlags & NV50_IR_DEBUG_VERBOSE)
       nir_print_shader(nir, stderr);
 
-   struct nir_lower_subgroups_options subgroup_options = {
-      .subgroup_size = 32,
-      .ballot_bit_size = 32,
-      .lower_elect = true,
-   };
+   struct nir_lower_subgroups_options subgroup_options = {};
+   subgroup_options.subgroup_size = 32;
+   subgroup_options.ballot_bit_size = 32;
+   subgroup_options.lower_elect = true;
 
    /* prepare for IO lowering */
    NIR_PASS_V(nir, nir_opt_deref);