riscv: Generate devicetree only after machine initialization is complete

riscv: Generate devicetree only after machine initialization is complete

If the devicetree is created before machine initialization is complete,
it misses dynamic devices. Specifically, the tpm device is not added
to the devicetree file and is therefore not instantiated in Linux.
Load/create devicetree in virt_machine_done() to solve the problem.

Cc: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Cc: Alistair Francis <alistair23@gmail.com>
Cc: Daniel Henrique Barboza <dbarboza@ventanamicro.c>
Fixes: 325b7c4e75 hw/riscv: Enable TPM backends
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230706035937.1870483-1-linux@roeck-us.net>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>