initramfs: remove duplicate built-in __initramfs_start unpacking

If initrd_start cpio extraction fails, CONFIG_BLK_DEV_RAM triggers
fallback to initrd.image handling via populate_initrd_image().
The populate_initrd_image() call follows successful extraction of any
built-in cpio archive at __initramfs_start, but currently performs
built-in archive extraction a second time.

Prior to commit b2a74d5f ("initramfs: remove clean_rootfs"),
the second built-in initramfs unpack call was used to repopulate entries
removed by clean_rootfs(), but it's no longer necessary now the contents
of the previous extraction are retained.
Signed-off-by: David Disseldorp <ddiss@suse.de>
Link: https://lore.kernel.org/r/20240111062240.9362-1-ddiss@suse.deReviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

init/initramfs.c

@@ -679,8 +679,6 @@ static void __init populate_initrd_image(char *err)
 	struct file *file;
 	loff_t pos = 0;
 
-	unpack_to_rootfs(__initramfs_start, __initramfs_size);
-
 	printk(KERN_INFO "rootfs image is not initramfs (%s); looks like an initrd\n",
 			err);
 	file = filp_open("/initrd.image", O_WRONLY | O_CREAT, 0700);