selftest: hid: add missing run-hid-tools-tests.sh

HID test cases run tests using the run-hid-tools-tests.sh script.
When installed with "make install", the run-hid-tools-tests.sh
script will not be copied over, resulting in the following error message.

  make -C tools/testing/selftests/ TARGETS=hid install \
  	  INSTALL_PATH=$KSFT_INSTALL_PATH

  cd $KSFT_INSTALL_PATH
  ./run_kselftest.sh -c hid

selftests: hid: hid-core.sh
bash: ./run-hid-tools-tests.sh: No such file or directory

Add the run-hid-tools-tests.sh script to the TEST_FILES in the Makefile
for it to be installed.

Fixes: ffb85d5c ("selftests: hid: import hid-tools hid-core tests")
Signed-off-by: Yun Lu <luyun@kylinos.cn>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>