dm: use DMDEBUG macros now that they use pr_debug variants

Now that DMDEBUG uses pr_debug and DMDEBUG_LIMIT uses
pr_debug_ratelimited cleanup DM's 2 direct pr_debug callers to use
them to get the benefit of consistent DM_FMT formatting of debugging
messages.

While doing so, dm-mpath.c:dm_report_EIO() was switched over to using
DMDEBUG_LIMIT due to the potential for error handling floods in the IO
completion path.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-mpath.c

@@ -439,7 +439,7 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
 }
 
 /*
- * dm_report_EIO() is a macro instead of a function to make pr_debug()
+ * dm_report_EIO() is a macro instead of a function to make pr_debug_ratelimited()
  * report the function name and line number of the function from which
  * it has been invoked.
  */
@@ -447,7 +447,7 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes)
 do {									\
 	struct mapped_device *md = dm_table_get_md((m)->ti->table);	\
 									\
-	pr_debug("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d\n", \
+	DMDEBUG_LIMIT("%s: returning EIO; QIFNP = %d; SQIFNP = %d; DNFS = %d", \
 		      dm_device_name(md),				\
 		      test_bit(MPATHF_QUEUE_IF_NO_PATH, &(m)->flags),	\
 		      test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &(m)->flags), \

drivers/md/dm.c

@@ -2609,7 +2609,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
 	if (noflush)
 		set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
 	else
-		pr_debug("%s: suspending with flush\n", dm_device_name(md));
+		DMDEBUG("%s: suspending with flush", dm_device_name(md));
 
 	/*
 	 * This gets reverted if there's an error later and the targets