Updated the documentation for creating rootfs sample. Apart from procfs and devfs, sysfs could also get mounted on boot.
Updated the documentation for creating rootfs sample.
Apart from procfs and devfs, sysfs could also get mounted on boot.

Signed-off-by: Ishwor Gurung <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@ishworgurung.com>

firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker