staging: lustre: discard libcfs_kvzalloc and linux-mem.c

staging: lustre: discard libcfs_kvzalloc and linux-mem.c

The only interesting difference between libcfs_kvzalloc()
and kvzalloc() is that the former appears to work
with GFP_NOFS, which the latter gives a WARN_ON_ONCE()
when that is attempted.

Each libcfs_kvzalloc() should really be analysed
and either converted to a kzalloc() call if the size is never
more than a page, or to use GFP_KERNEL if no locks are held.

If there is ever a case where locks are held and a large allocation
is needed, then some other technique should be used.

It might be nice to not always blindly zero pages too...

For now, just convert libcfs_kvzalloc() calls to
kvzalloc(), and let the warning remind us that there is work to do.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>