gnu: libtgvoip: Fix failing build on i686-linux.

gnu: libtgvoip: Fix failing build on i686-linux.

* gnu/local.mk (libtgvoip): Add patches for libtgvoip-disable-sse2.patch
and libtgvoip-disable-webrtc.patch

* gnu/packages/patches/libtgvoip-disable-sse2.patch: New file.

* gnu/packages/patches/libtgvoip-disable-webrtc.patch: New file.

* gnu/packages/telephony.scm (libtgvoip): Fix building on i686-linux.
[source]: Reference patches for correcting failing build on i686-linux
architecture.

Reported-by: Diego Nicola Barbato <dnbarbato@posteo.de>
Fixes <bugs.gnu.org/38944>.