BoardConfig: needed to please bionic
audio: fixes for 4.3
config.xml: remove deprecated value
HuaweiQualcommRIL: bring-up for 4.3
system.prop: huawei pls
fstab: fixes for 4.3

* rename fstab.u8815 to fstab.huawei so vold guesses the right name (ro.hardware)
* remove deprecated vold.fstab, merge with fstab.huawei
Update patches for 4.3
wifi.c: update for 4.3
system.prop: update max background apps key