Local variable i is unsigned int and thus cannot be negative.

(akpm: unsigneds shouldn't be called `i'.  This value cannot possibly be
negative anyway).
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>