ppc: free 'fdt' after reset the machine

ppc: free 'fdt' after reset the machine

'fdt' forgot to clean both e500 and pnv when we call 'system_reset' on ppc,
this patch fix it. The leak stacks are as follow:

Direct leak of 4194304 byte(s) in 4 object(s) allocated from:
    #0 0x7fafe37dd970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970)
    #1 0x7fafe2e3149d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d)
    #2 0x561876f7f80d in create_device_tree /mnt/sdb/qemu-new/qemu/device_tree.c:40
    #3 0x561876b7ac29 in ppce500_load_device_tree /mnt/sdb/qemu-new/qemu/hw/ppc/e500.c:364
    #4 0x561876b7f437 in ppce500_reset_device_tree /mnt/sdb/qemu-new/qemu/hw/ppc/e500.c:617
    #5 0x56187718b1ae in qemu_devices_reset /mnt/sdb/qemu-new/qemu/hw/core/reset.c:69
    #6 0x561876f6938d in qemu_system_reset /mnt/sdb/qemu-new/qemu/vl.c:1412
    #7 0x561876f6a25b in main_loop_should_exit /mnt/sdb/qemu-new/qemu/vl.c:1645
    #8 0x561876f6a398 in main_loop /mnt/sdb/qemu-new/qemu/vl.c:1679
    #9 0x561876f7da8e in main /mnt/sdb/qemu-new/qemu/vl.c:4438
    #10 0x7fafde16b812 in __libc_start_main ../csu/libc-start.c:308
    #11 0x5618765c055d in _start (/mnt/sdb/qemu-new/qemu/build/ppc64-softmmu/qemu-system-ppc64+0x2b1555d)

Direct leak of 1048576 byte(s) in 1 object(s) allocated from:
    #0 0x7fc0a6f1b970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970)
    #1 0x7fc0a656f49d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d)
    #2 0x55eb05acd2ca in pnv_dt_create /mnt/sdb/qemu-new/qemu/hw/ppc/pnv.c:507
    #3 0x55eb05ace5bf in pnv_reset /mnt/sdb/qemu-new/qemu/hw/ppc/pnv.c:578
    #4 0x55eb05f2f395 in qemu_system_reset /mnt/sdb/qemu-new/qemu/vl.c:1410
    #5 0x55eb05f43850 in main /mnt/sdb/qemu-new/qemu/vl.c:4403
    #6 0x7fc0a18a9812 in __libc_start_main ../csu/libc-start.c:308
    #7 0x55eb0558655d in _start (/mnt/sdb/qemu-new/qemu/build/ppc64-softmmu/qemu-system-ppc64+0x2b1555d)

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Message-Id: <20200214033206.4395-1-pannengyuan@huawei.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>