tcg: Convert muluh to TCGOutOpBinary

Remove unreachable mul[su]h_i32 leftovers from commit aeb6326ec5
("tcg/riscv: Require TCG_TARGET_REG_BITS == 64").

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/arm/tcg-target.c.inc

@@ -1890,6 +1890,10 @@ static const TCGOutOpBinary outop_mul = {
     .out_rrr = tgen_mul,
 };
 
+static const TCGOutOpBinary outop_muluh = {
+    .base.static_constraint = C_NotImplemented,
+};
+
 static const TCGOutOpBinary outop_nand = {
     .base.static_constraint = C_NotImplemented,
 };