hw/riscv: hart: Add a new 'resetvec' property

RISC-V machines do not instantiate RISC-V CPUs directly, instead
they do that via the hart array. Add a new property for the reset
vector address to allow the value to be passed to the CPU, before
CPU is realized.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <1598924352-89526-3-git-send-email-bmeng.cn@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

include/hw/riscv/riscv_hart.h

@@ -37,6 +37,7 @@ typedef struct RISCVHartArrayState {
     uint32_t num_harts;
     uint32_t hartid_base;
     char *cpu_type;
+    uint64_t resetvec;
     RISCVCPU *harts;
 } RISCVHartArrayState;