v3d: Enable NIR's lower_fmod option.

Currently, st/mesa is always calling the GLSL IR lower_instructions()
pass with MOD_TO_FLOOR set, so mod operations will be lowered before
ever reaching NIR.  This enables the same lowering at the NIR level,
which will let me shut off the GLSL IR path for NIR-based drivers.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Acked-by: Eric Anholt <eric@anholt.net>

src/broadcom/compiler/nir_to_vir.c

@@ -2382,6 +2382,7 @@ const nir_shader_compiler_options v3d_nir_options = {
         .lower_bit_count = true,
         .lower_cs_local_id_from_index = true,
         .lower_ffract = true,
+        .lower_fmod = true,
         .lower_pack_unorm_2x16 = true,
         .lower_pack_snorm_2x16 = true,
         .lower_pack_unorm_4x8 = true,