selftests/powerpc: fix exec benchmark

[Michael Ellerman]

On Sat, 2018-05-12 at 03:35:24 UTC, Nicholas Piggin wrote:
> The exec_target binary could segfault calling _exit(2) because r13
> is not set up properly (and libc looks at that when performing a
> syscall). Call SYS_exit using syscall(2) which doesn't seem to
> have this problem.
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/c906d2c74e0bb9059fbf43e21f8a96

cheers