Handle the Facility Unavailable exception as a SIGILL
Currently Facility Unavailable is absent and once an application
tries to use or access a register from a feature disabled in the
CPU it causes a kernel panic.
A simple test-case is:
int main() { asm volatile ("tbegin.;"); }
which will use TM (Hardware Transactional Memory) feature which
is not supported by the kernel and so will trigger the following
kernel panic: