moving to initramfs unifies disk allocate on different platforms.
use fallocate instead of dd to speed up the disk allocation.
By default, mkfs.ext4 has -E discard option which discards the blocks
at the mkfs time, also speed up the initialization time.
* Bump sonic-platform-modules-arista submodule
* Use sonic_sfputil plugin from the arista library
* Fix undefined variable varlog_size
* Prevent minigraph.xml to be removed from the flash
* Update DCS-7050QX-32 sensors config
