Please include pagemap header cleanup in -next

[Matthew Wilcox]

Hi Mark,

As discussed on IRC, please include

git://git.infradead.org/users/willy/pagecache.git headers

The net effect is to reduce the number of files depending on pagemap.h
from ~9100 to ~1400 on an x86 allmodconfig build.  The Intel test robot
has been steadily building random configs on random architectures and
finding new missing includes, so there may be some build breakages that
it hasn't tested.

My plan is to send this to Linus on Thursday or Friday.  I don't see the
point in letting it soak longer; any problems it causes are build
problems.