UBIFS: comply with coding style

Join all the split printk lines in order to stop checkpatch complaining.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 7bd6e72..ff48c5a 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1486,8 +1486,8 @@
 	err = ubifs_budget_space(c, &req);
 	if (unlikely(err)) {
 		if (err == -ENOSPC)
-			ubifs_warn("out of space for mmapped file "
-				   "(inode number %lu)", inode->i_ino);
+			ubifs_warn("out of space for mmapped file (inode number %lu)",
+				   inode->i_ino);
 		return VM_FAULT_SIGBUS;
 	}