Use kernel-provided bit rotation and unaligned access infrastructure rather
than opencoding it.

Some minor spacing adjustments as well.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>