By default, sorting is done by the display role, but then we end up
sorting by the string we display, which is almost always the wrong thing.
So this adds a new "SORT_ROLE" that is used for sorting, and then the
data lookup can return the raw data we want to sort by.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>