fix(st): add missing files for ECDSA compilations

The tf_config files were added by patch [1], but the tf-l1-build-plat
files were not added. Add them now.

[1] ("feat(st): add the TRUSTED_BOARD_BOOT build config")

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I4bb759db217a741246f0fe88a571e683dd159707
2 files changed