[arm] fix syscall_uname memory write bug
[arm] fix syscall_uname memory write bug

cornell-brg/pydgin,cornell-brg/pydgin,cornell-brg/pydgin,futurecore/pydgin,cornell-brg/pydgin,futurecore/pydgin,futurecore/pydgin,moreati/pydgin,moreati/pydgin,moreati/pydgin,moreati/pydgin,futurecore/pydgin