Replace the FIT() macro with the kernel-provided clamp_val() macro.

FIT was always being called with a member of a struct ide_timing,
which are shorts, and constant constraints for the min and max.

Thus we can use clamp_val, rather than clamp_t.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>