The magic numbers of the length are converted to their actual meaning,
such as end of the buffer with and without ASCII part.

We don't touch the rest of the magic constants that will be removed in the
following commits.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>