Get rid of the x86 SSE code for atomic 64-bit writes to doorbell registers.
Saving/setting CR0 plus a clts instruction are too expensive for it to ever be
a win, and the config option was just confusing.
Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>