intelfb: fix spelling of "CLOCK"

Signed-off-by: Pavel Roskin <proski@gnu.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>