undeprecate raw driver

Despite repeated attempts over the last two and half years, this driver
seems somewhat persistant.  Remove its deprecated status as it has existing
users who may not be in a position to migrate their apps to O_DIRECT.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>