tools/vm/slabinfo: order command line options

During recent discussion on LKML over SLAB vs SLUB it was suggested by
Jesper that it would be nice to have a tool to view the current
fragmentation of the slab allocators.  CC list for this set is taken
from that thread.

For SLUB we have all the information for this already exposed by the
kernel and also we have a userspace tool for displaying this info:

	tools/vm/slabinfo.c

Extend slabinfo to improve the fragmentation information by enabling
sorting of caches by number of partial slabs.

Also add cache list sorted in this manner to the output of `slabinfo -X`.

This patch (of 4):

get_opt() has a spurious character within the option string.  Remove it
and reorder the options in alphabetic order so that it is easier to keep
the options correct.  Use the same ordering for command help output and
long option handling code.

Link: http://lkml.kernel.org/r/20190426022622.4089-2-tobin@kernel.org
Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Pekka Enberg <penberg@iki.fi>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>,
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>