ix init script duplication and CPIO creation issues

- Remove duplicate /sbin/init copying from initramfs_setup_zinit()
- Only /init should be config/init (initramfs setup script)
- No /sbin/init needed - config/init calls 'switch_root /mnt/root /sbin/zinit init'
- Remove unsupported cpio --owner option that broke CPIO creation
- Fix validation to not expect /sbin/init file
- Correct boot flow: /init → switch_root → /sbin/zinit init
- Remove strip and UPX compression from zinit binary copying
- UPX compression was corrupting the zinit binary causing segfaults after switch_root
- Keep zinit unmodified as it's

initramfs/etc/apk/world

@@ -20,7 +20,6 @@ libc-utils
 linux-firmware-bnx2
 linux-firmware-e100
 linux-firmware-intel
-linux-firmware-mellanox
 linux-firmware-qlogic
 linux-firmware-realtek
 musl