Revert "busybox: remove SYSTEM-to-RAM support, it dont improves much"

This reverts commit 2839726b0e14d9b99fc51a12f3b175546137d6ce.
busybox: remove support for initramfs.conf, disable SYSTEM-to-RAM support for RPi

Signed-off-by: Stephan Raue <stephan@openelec.tv>
util-linux: update to util-linux-2.25

Signed-off-by: Stephan Raue <stephan@openelec.tv>
libXext: update to libXext-1.3.3

Signed-off-by: Stephan Raue <stephan@openelec.tv>