selftests: tpm2: create a dedicated .gitignore

The tpm2 selftests produce two logs: SpaceTest.log and
AsyncTest.log. Only SpaceTest.log was listed in selftests/.gitignore,
while AsyncTest.log remained untracked.

This change creates a dedicated .gitignore in the tpm2/ directory to
manage these entries, keeping tpm2-specific patterns isolated from
parent .gitignore.

Fixed white-space errors during commit
Shuah Khan <[e-mail]>

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Khaled Elnaggar <[e-mail]>
Reviewed-by: Jarkko Sakkinen <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/.gitignore

···
 gpioinclude/
 gpiolsgpio
 kselftest_install/
-tpm2/SpaceTest.log
 
 # Python bytecode and cache
 __pycache__/

tools/testing/selftests/tpm2/.gitignore

···
+# SPDX-License-Identifier: GPL-2.0-only
+AsyncTest.log
+SpaceTest.log