package/wolfssl: disable examples and tests

package/wolfssl: disable examples and tests

Examples and tests are not needed especially because of them fails on
some architectures because it wrongly tries to use wc_Sha256FinalRaw:

  CCLD     tests/unit.test
/tmp/instance-0/output-1/host/opt/ext-toolchain/bin/../lib/gcc/aarch64-none-linux-gnu/9.2.1/../../../../aarch64-none-linux-gnu/bin/ld: tests/tests_unit_test-api.o: in function `test_wc_Sha256FinalRaw':
/tmp/instance-0/output-1/build/wolfssl-4.5.0-stable/tests/api.c:6504: undefined reference to `wc_Sha256FinalRaw'

Fixes:
 - http://autobuild.buildroot.org/results/d5b6f97f7510874fe28c675e599be08cb8a78c7b

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>