fix(plat/marvell/a3k): Fix check for external dependences

Old Marvell a3700_utils and mv-ddr tarballs do not have to work with
latest TF-A code base. Marvell do not provide these old tarballs on
Extranet anymore. Public version on github repository contains all
patches and is working fine, so for public TF-A builds use only public
external dependencies from git.

Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: Iee5ac6daa9a1826a5b80a8d54968bdbb8fe72f61
2 files changed