devtmpfs: convert to pr_fmt

Use the pr_fmt() macro to prefix all the output with "devtmpfs: ".
while at it, convert printk(<LEVEL>) to pr_<level>().
Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230202033203.1239239-2-xialonglong1@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/devtmpfs.c

@@ -13,6 +13,8 @@
  * overwrite the default setting if needed.
  */
 
+#define pr_fmt(fmt) "devtmpfs: " fmt
+
 #include <linux/kernel.h>
 #include <linux/syscalls.h>
 #include <linux/mount.h>
@@ -376,9 +378,9 @@ int __init devtmpfs_mount(void)
 
 	err = init_mount("devtmpfs", "dev", "devtmpfs", DEVTMPFS_MFLAGS, NULL);
 	if (err)
-		printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
+		pr_info("error mounting %d\n", err);
 	else
-		printk(KERN_INFO "devtmpfs: mounted\n");
+		pr_info("mounted\n");
 	return err;
 }
 
@@ -460,14 +462,12 @@ int __init devtmpfs_init(void)
 
 	mnt = vfs_kern_mount(&internal_fs_type, 0, "devtmpfs", opts);
 	if (IS_ERR(mnt)) {
-		printk(KERN_ERR "devtmpfs: unable to create devtmpfs %ld\n",
-				PTR_ERR(mnt));
+		pr_err("unable to create devtmpfs %ld\n", PTR_ERR(mnt));
 		return PTR_ERR(mnt);
 	}
 	err = register_filesystem(&dev_fs_type);
 	if (err) {
-		printk(KERN_ERR "devtmpfs: unable to register devtmpfs "
-		       "type %i\n", err);
+		pr_err("unable to register devtmpfs type %d\n", err);
 		return err;
 	}
 
@@ -480,12 +480,12 @@ int __init devtmpfs_init(void)
 	}
 
 	if (err) {
-		printk(KERN_ERR "devtmpfs: unable to create devtmpfs %i\n", err);
+		pr_err("unable to create devtmpfs %d\n", err);
 		unregister_filesystem(&dev_fs_type);
 		thread = NULL;
 		return err;
 	}
 
-	printk(KERN_INFO "devtmpfs: initialized\n");
+	pr_info("initialized\n");
 	return 0;
 }