target/riscv: Convert RV64I load/store insns to decodetree

this splits the 64-bit only instructions into its own decode file such
that we generate the decoder for these instructions only for the RISC-V
64 bit target.

Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Signed-off-by: Peer Adelt <peer.adelt@hni.uni-paderborn.de>

target/riscv/insn_trans/trans_rvi.inc.c

@@ -130,3 +130,23 @@ static bool trans_sw(DisasContext *ctx, arg_sw *a)
     gen_store(ctx, OPC_RISC_SW, a->rs1, a->rs2, a->imm);
     return true;
 }
+
+#ifdef TARGET_RISCV64
+static bool trans_lwu(DisasContext *ctx, arg_lwu *a)
+{
+    gen_load(ctx, OPC_RISC_LWU, a->rd, a->rs1, a->imm);
+    return true;
+}
+
+static bool trans_ld(DisasContext *ctx, arg_ld *a)
+{
+    gen_load(ctx, OPC_RISC_LD, a->rd, a->rs1, a->imm);
+    return true;
+}
+
+static bool trans_sd(DisasContext *ctx, arg_sd *a)
+{
+    gen_store(ctx, OPC_RISC_SD, a->rs1, a->rs2, a->imm);
+    return true;
+}
+#endif