tile: remove MAP_CACHE_xxx support in mem.c

tile: remove MAP_CACHE_xxx support in mem.c

These flags support functionality in mmap() that has not been
pushed back to the community, and which may or may not eventually
end up being the final community model.  In the interim, having
these flags unconditionally present for "#ifdef TILE" just means
that the TILE build breaks if using the community versions of
the kernel and glibc, so just revert the code until such time
as it may end up in the community.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>