radv: spir-v allows texture size query with and without lod.

The translation to llvm was failing here due to required lod.

This fixes some new  SteamVR shaders.

Cc: "13.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

src/amd/common/ac_nir_to_llvm.c

@@ -3492,7 +3492,10 @@ static void visit_tex(struct nir_to_llvm_context *ctx, nir_tex_instr *instr)
 		address[count++] = sample_index;
 	} else if(instr->op == nir_texop_txs) {
 		count = 0;
-		address[count++] = lod;
+		if (lod)
+			address[count++] = lod;
+		else
+			address[count++] = ctx->i32zero;
 	}
 
 	for (chan = 0; chan < count; chan++) {