[Nexus 5] Add nougat support (aosp and cm)
Add kernels for Nexus 5 Nougat. The kernels are for AOSP 7 and CyanogenMod 14.1 CAF. They are patched for the DirtyCOW vulnerability, have Kexec-hardboot support (I needed this so I did it, not relevant to nethunter but doesn't hurt) and have been tested. The one for CM is used as a daily driver.