TF-M: set git default config

cppcheck test requires to build mbedcrypto, which fails with a cmake
fatal error: fatal: unable to auto-detect email address

Set a git default config to avoid this error.

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: Ice1337777ea294e0b93c573137fa9780c544a864
1 file changed