arch/tile: kernel-related cleanups from removing static page size

User space code has been able to discover the static page size
by including a special <hv/pagesize.h> file.  In the current release,
that file is now gone, and <asm/page.h> doesn't rely on it.  The
getpagesize() API is now the only way for userspace to get the page size.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>