Merge r190708 from HEAD to releng/7.2:

Merge r190708 from HEAD to releng/7.2:
Fix KBI breakage by r190520 which affects older linux.ko binaries:

1) Move the new field (brand_note) to the end of the Brandinfo structure.
2) Add a new flag BI_BRAND_NOTE that indicates that the brand_note pointer
   is valid.
3) Use the brand_note field if the flag BI_BRAND_NOTE is set and as old
   modules won't have the flag set, so the new field brand_note would be
   ignored.

Suggested by:   jhb
Reviewed by:    jhb

Approved by:	re (Ken Smith), kib (mentor)

git-svn-id: svn://svn.freebsd.org/base/releng/7.2@191213 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f