[PATCH] ia64 uncached alloc

This patch contains the ia64 uncached page allocator and the generic
allocator (genalloc).  The uncached allocator was formerly part of the SN2
mspec driver but there are several other users of it so it has been split
off from the driver.

The generic allocator can be used by device driver to manage special memory
etc.  The generic allocator is based on the allocator from the sym53c8xx_2
driver.

Various users on ia64 needs uncached memory.  The SGI SN architecture requires
it for inter-partition communication between partitions within a large NUMA
cluster.  The specific user for this is the XPC code.  Another application is
large MPI style applications which use it for synchronization, on SN this can
be done using special 'fetchop' operations but it also benefits non SN
hardware which may use regular uncached memory for this purpose.  Performance
of doing this through uncached vs cached memory is pretty substantial.  This
is handled by the mspec driver which I will push out in...