selftests: tpm2: install python files

Both test_smoke.sh and test_space.sh require tpm2.py and tpm2_test.py.

Rework so that tpm2.py and tpm2_test.py gets installed, added them to
the variable TEST_PROGS_EXTENDED.

Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>