btrfs: switch more printks to our helpers

Convert the simple cases, not all functions provide a way to reach the
fs_info. Also skipped debugging messages (print-tree, integrity
checker and pr_debug) and messages that are printed from possibly
unfinished mount.

Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index aa72bfd..4ea07c8 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -2562,7 +2562,7 @@
 	} else if (S_ISSOCK(mode)) {
 		cmd = BTRFS_SEND_C_MKSOCK;
 	} else {
-		printk(KERN_WARNING "btrfs: unexpected inode type %o",
+		btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o",
 				(int)(mode & S_IFMT));
 		ret = -ENOTSUPP;
 		goto out;