As per [1] Intel only supports this driver on 64bit platforms.
For now restrict it to amd64.  Other architectures might be
re-added later once tested.

Remove the drivers from the global NOTES and files files and move
them to the amd64 specifics.
Remove the drivers from the i386 modules build and only leave the
amd64 version.

Rather than depending on "inet" depend on "pci" and make sure that
ixl(4) and ixlv(4) can be compiled independently [2].  This also
allows the drivers to build properly on IPv4-only or IPv6-only
kernels.

PR:		193824 [2]
Reviewed by:	eric.joyner intel.com
MFC after:	3 days

References:
[1] http://lists.freebsd.org/pipermail/svn-src-all/2014-August/090470.html
Given we are restricting ixl(4) to 64bit platforms now backout the change
r270820 to common (shared) Intel code no longer needed.

MFC after:	3 days