hw/avr/atmega: Fix wrong initial value of stack pointer

The current implementation initializes the stack pointer of AVR devices
to 0. Although older AVR devices used to be like that, newer ones set
it to RAMEND.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1525
Signed-off-by: Gihun Nam <gihun.nam@outlook.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <PH0P222MB0010877445B594724D40C924DEBDA@PH0P222MB0010.NAMP222.PROD.OUTLOOK.COM>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
3 files changed