Log Message:
binutils: remove CFLAGS.OpenBSD+= -Wno-bounded directive.

This was added in 2014 in r1.57 along with patches to add OpenBSD/amd64
5.4 support, which have long been removed.

In OpenBSD 6.2, the default compiler on amd64 was switched from GCC to
Clang, which does not support this option and emits unknown warning
option '-Wno-bounded' warnings.