msm8974-common: Clean up Samsung device inheritance

* Remove duplicate keylayouts
* Move media_codecs to platform tree
* Unconditionally build consumerir
* Move postrecoveryboot to qcom-common
* Move common msm8974 HAL/packages to platform tree
* Move wifi config to device trees
* Use nested cm.dependencies
* Generate firmware symlinks at compile time
* Move egl.cfg to msm8974-common
* Move QCOM_BSP to platform repos
* Move telephony permissions to device
* Move reboot to download option to qcom-common
* Move common overlay options to qcom-common

Change-Id: I493dcf24269e852e7819c045dc3afc5c47da176a