buildroot

bump linux kernel versions

Bump all the linux kernel version to the latest available and add a
help note for all of them with the release data and status.

The long-term stable 2.6.27 kernel is really out of date (.27 -> .45).

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>