package/ne10: disable unit tests and examples

Unit tests fail to build with gcc 10 on:

[100%] Linking C executable NE10_dsp_unit_test_smoke
/home/buildroot/autobuild/instance-2/output-1/host/opt/ext-toolchain/bin/../lib/gcc/aarch64-none-linux-gnu/10.2.1/../../../../aarch64-none-linux-gnu/bin/ld: CMakeFiles/NE10_dsp_unit_test_static.dir/__/modules/dsp/test/test_suite_fft_float32.c.o:(.bss+0x0): multiple definition of `seatest_simple_test_result'; CMakeFiles/NE10_dsp_unit_test_static.dir/__/modules/dsp/test/test_main.c.o:(.bss+0x0): first defined here

So just disable them and, while at it, also disable examples which are
also enabled by default

Fixes:
 - http://autobuild.buildroot.org/results/c658d52668825c26a15d6ac3ca538472cad5cd78



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>