mkbootfs - Support to read canned config file.

N/A

Signed-off-by: liminghao <vgotoos@gmail.com>
mount four filesystem in ramdisk.

N/A

four filesystem: tmpfs, proc, pts, sysfs.

Signed-off-by: liminghao <vgotoos@gmail.com>
Implement to klog for init.

N/A

Signed-off-by: liminghao <liminghao@xiaomi.com>