Boeffla ramfs: Finetuning of startup script to fix rare issues with external SD cards

Reason is still not 100%, but it seems setting the readahead buffers late in the
kernel start process or the remounting of /data and /cache with a commit time causes
the issues for some percent of the users.
Boeffla ramfs: Hardening by additional syncs in bccontroller.sh

avoiding sporadic issues like modules not completely copied during CM kernel flash, etc.
Boeffla Ramfs: Improve reset script to wipe complete .boeffla folder in data

... in order to delete also frandom and busybox settings files
charge_level: Improved sysfs input validation
Boeffla Sound: Improved sysfs input validation
mms_ts: Touchboost switch - improved sysfs input validation
mdnie: Switchable sharpness fix - improved sysfs input validation
Touch to wake: Improved sysfs input validation
Boeffla Ramfs: Bump reset script to version V3
Boeffla Sound: Fixed bug in improved sysfs input validation
Release tag: 2.4-beta6
Merge remote-tracking branch 'upstream/boeffla' into boeffla
merge upstream branch andip71/boeffla