... and simplify the results a bit.  Makes the next step easier
to deal with - we will be changing the data representation for
chunk->map[] and it's easier to do if the code in question is
not split between pcpu_alloc_area() and pcpu_split_block().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NTejun Heo <tj@kernel.org>