Fix hwpmc sampling for ppc970 (G5-class) processors.

With this, hwpmc sampling now works on these processors.

MFC after:	3 weeks
Relnotes:	yes
Revert part of r275059. Comparing unsigned 8 bit value
against -'0' is always false so the conditional block is
optimized away.
Copy elftoolchain binutils replacements from vendor branch

Sponsored by:	The FreeBSD Foundation
Put each SUBDIR on a separate line

This makes it easier to review or merge changes that modify some subset
of SUBDIRs.
Remove leftovers readline being changed to an internallib
Do not try to copy header to @dst and than back to ethernet in case of
pseudo_AF_HDRCMPLT:

we copy media header from mbuf to 'struct sockaddr' @dst in bpf_movein, so
mbuf already contains valid info.