package/netopeer2: disable tests

Disable tests which are enabled since bump to version 2.0.35 in commit
13d4856b916d797c3c771669edd3eb883336766f and
https://github.com/CESNET/netopeer2/commit/466a0b3c268ee319b4f65980404715a2723b4c0a
to avoid the following build failure if cmocka is built before
netopeer2:

In file included from /home/buildroot/autobuild/instance-2/output-1/host/riscv64-buildroot-linux-musl/sysroot/usr/include/stdint.h:20,
                 from /home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/lib/gcc/riscv64-buildroot-linux-musl/10.3.0/include/stdint.h:9,
                 from /home/buildroot/autobuild/instance-2/output-1/host/riscv64-buildroot-linux-musl/sysroot/usr/include/libyang/libyang.h:18,
                 from /home/buildroot/autobuild/instance-2/output-1/build/netopeer2-2.0.35/tests/test_sub_ntf.c:27:
/home/buildroot/autobuild/instance-2/output-1/host/riscv64-buildroot-linux-musl/sysroot/usr/include/bits/alltypes.h:53:24: error: conflicting types for 'uintptr_t'
   53 | typedef unsigned _Addr uintptr_t;
      |                        ^~~~~~~~~

Fixes:
 - http://autobuild.buildroot.org/results/0660a4f767d5cdaf07b28a508101b87f0300850f

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Reviewed-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/netopeer2/netopeer2.mk

@@ -11,7 +11,9 @@ NETOPEER2_LICENSE = BSD-3-Clause
 NETOPEER2_LICENSE_FILES = LICENSE
 NETOPEER2_DEPENDENCIES = libnetconf2 libyang sysrepo host-sysrepo
 
-NETOPEER2_CONF_OPTS = -DBUILD_CLI=$(if $(BR2_PACKAGE_NETOPEER2_CLI),ON,OFF)
+NETOPEER2_CONF_OPTS = \
+	-DBUILD_CLI=$(if $(BR2_PACKAGE_NETOPEER2_CLI),ON,OFF) \
+	-DENABLE_TESTS=OFF
 
 # Set a build specific SYSREPO_SHM_PREFIX to ensure we can safely delete the
 # files. This also ensures that concurrent parallel builds will not be