Do not support loading modules from "deviceinfo_modules_initfs" (MR 38)

This variable will dissappear from the deviceinfo at some point:
https://gitlab.com/postmarketOS/pmaports/-/merge_requests/4169
so after it does, it would not make much sense to keep its use around

pkgs/deviceinfo/deviceinfo.go

@@ -19,7 +19,6 @@ type DeviceInfo struct {
 	InitfsCompression      string
 	InitfsExtraCompression string
 	MesaDriver             string
-	ModulesInitfs          string
 	UbootBoardname         string
 }