FreeBSD/mips uses an optional "0" argument to ".ent", which is supported by
gas but not by LLVM-MC.  As the 0 appears not to do anything (according to
one web page I found, it's for OSF/1 compatibility!), remove it from
CheriBSD.  It may be desirable for LLVM-MC to support this feature in the
future, in its attempt to generally be gas-compatible.