package/wvstreams: mark as deprecated

package/wvstreams: mark as deprecated

As reported by Jörg and I [1] [2], wvstreams is not maintained anymore. Last
activity was on Github was 2011, the current version 1.6.1 dates from 2009.

Also it doesn't build anymore with a recent compiler (gcc5 and gcc6).
Instead of stacking patches forever, mark this wvstreams and wvdial deprecated
before removing them completely.

Remove following failures from autobuilders.
http://autobuild.buildroot.net/results/f01/f0166f030875ecaf0d757790de6361339071831e
http://autobuild.buildroot.net/results/32b/32b4eba8c7cbe8a3b1cde2d67f1af3f913fcc292
http://autobuild.buildroot.net/results/38f/38fefa126596c6e267ffaf0f2dd9c5e3dcf09aff
http://autobuild.buildroot.net/results/ea2/ea223c8a4f817541f55aa36c47b159a316031bff

[1] http://patchwork.ozlabs.org/patch/674238/
[2] http://patchwork.ozlabs.org/patch/505304/

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Simon Dawson <spdawson@gmail.com>
Cc: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>