hw/m68k/mcf52xx: Replace hw_error() by qemu_log_mask()

hw/m68k/mcf52xx: Replace hw_error() by qemu_log_mask()

hw_error() calls exit(). This a bit overkill when we can log
the accesses as unimplemented or guest error.

When fuzzing the devices, we don't want the whole process to
exit. Replace some hw_error() calls by qemu_log_mask().

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200526094052.1723-3-f4bug@amsat.org>
Reviewed-by: Thomas Huth <huth@tuxfamily.org>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>