The working flow of new feature is:
->bootloader decompress ramdisk.gz to cpio data first and start kernel.
->decompressor driver notify initramfs that cpio data ready.
->initramfs continue to flush cpio data to rootfs.
Change-Id: I9cd5708fc93270ce77376c26d9da5a5c219996c1
Signed-off-by: Simon Xue <xxm@rock-chips.com>
Signed-off-by: Tao Huang <huangtao@rock-chips.com>