package/protozero: disable tests

package/protozero: disable tests

Add a patch to disable tests through the standard BUILD_TESTING variable
which is already passed by cmake-package.

While at it, drop protobuf dependency which is only needed for tests

This will fix a build failure on toolchains without wchar, toolchains
for sh4 (ICE) or toolchains where gcc is affected by bug 64735.

Upstream thinks that this is unecessary but no additional feedback was
received on how we should handle those build failures

Fixes:
 - http://autobuild.buildroot.org/results/1cd24b757d87b963c70bc7ff927c6d983d0b142a

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Reviewed-by: Maxim Kochetkov <fido_max@inbox.ru>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>