doc: Fix default value of 'mon_osd_max_split_count'

This commit is not cherry-picked from master because the config
parameter mon_osd_max_split_count has been dropped in master

Signed-off-by: Kai Wagner <kwagner@suse.com>
(cherry picked from commit 17d503f)

doc/rados/configuration/mon-config-ref.rst

@@ -1193,7 +1193,7 @@ Miscellaneous
               will be splitted on all OSDs serving that pool. We want to avoid
               extreme multipliers on PG splits.
 :Type: Integer
-:Default: 300
+:Default: 32
 
 
 ``mon session timeout``