Bug#1068583: libgav1: FTBFS on s390x: test failures

[Sebastiaan Couwenberg]

I've added architecture-is-little-endian to the build dependency in git 
to make the lack of big endian support explicit.

Kind Regards,
Bas

--
 GPG Key ID: 4096R/6750F10AE88D4AF1
Fingerprint: 8182 DE41 7056 408D 6146  50D1 6750 F10A E88D 4AF1