Mark net/litecoin BROKEN-sparc64?

[Kurt Mosiejczuk]

http://build-failures.rhaalovely.net/sparc64/2019-12-27/net/litecoin.log

I don't think I've ever seen litecoin finish on sparc64, and looking at
the log of the last failure it seems like it is hitting a clang failure.

Shall I mark it broken?

--Kurt