linux: Remove user-space probe support

linux: Remove user-space probe support

From the kernels' documentation:

> Uprobes is the user-space counterpart to kprobes: they
> enable instrumentation applications (such as 'perf probe')
> to establish unintrusive probes in user-space binaries and
> libraries, by executing handler functions when the probes
> are hit by user-space applications.
>
> ( These probes come in the form of single-byte breakpoints,
> managed by the kernel and kept transparent to the probed
> application. )

To the best of the authors' understanding, no application on IPFire
needs this functionality, and given its abuse potential, we should
probably not enable it.

As expected, strace functionality is not impaired by this.

Signed-off-by: Peter Müller <peter.mueller@ipfire.org>