target/riscv: Drop temp_new

Translators are no longer required to free tcg temporaries,
therefore there's no need to record temps for later freeing.
Replace the few uses with tcg_temp_new.

Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/riscv/insn_trans/trans_rvzfh.c.inc

@@ -51,7 +51,7 @@ static bool trans_flh(DisasContext *ctx, arg_flh *a)
     decode_save_opc(ctx);
     t0 = get_gpr(ctx, a->rs1, EXT_NONE);
     if (a->imm) {
-        TCGv temp = temp_new(ctx);
+        TCGv temp = tcg_temp_new();
         tcg_gen_addi_tl(temp, t0, a->imm);
         t0 = temp;
     }