MAINTAINERS: Add selftest files to TPM section

tools/testing/selftests/tpm2/ is TPM-specific test
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

MAINTAINERS

@@ -23308,6 +23308,7 @@ Q:	https://patchwork.kernel.org/project/linux-integrity/list/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd.git
 F:	Documentation/devicetree/bindings/tpm/
 F:	drivers/char/tpm/
+F:	tools/testing/selftests/tpm2/
 
 TPS546D24 DRIVER
 M:	Duke Du <dukedu83@gmail.com>