target/mips: Fix trans_mult_acc return

Success from trans_* subroutines should be true.

Fixes: 5fa38eedbd ("target/mips: Convert Vr54xx MACC* opcodes to decodetree")
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/mips/tcg/vr54xx_translate.c

@@ -53,7 +53,7 @@ static bool trans_mult_acc(DisasContext *ctx, arg_r *a,
     tcg_temp_free(t0);
     tcg_temp_free(t1);
 
-    return false;
+    return true;
 }
 
 TRANS(MACC,     trans_mult_acc, gen_helper_macc);