serrano-common: Clean up Samsung device inheritance

* Remove init.qcom.class_main and init.qcom.class_core
* Remove init.qcom.early_boot.sh
* Remove init.qcom.ril.sh
* Move init.qcom.syspart_fixup.sh to serrano-common
* Remove init.qcom.sh
* Move init.qcom.post_boot.sh to serrano-common
* Move init.qcom.thermal_conf.sh to serrano-common
* Remove init.qcom.usb.sh
* Move media_codecs.xml to serrano-common
* Remove unused init.qcom.mdm_links.sh
* Move common 8930 stuff out of here and into msm8930-common