User specified early platform devices will be registered at this point.
For the early serial console case the user can specify port on the
kernel command line as "earlyprintk=serial.0" where "earlyprintk" is
-the class string, "serial" is the name of the platfrom driver and
+the class string, "serial" is the name of the platform driver and
0 is the platform device id. If the id is -1 then the dot and the
id can be omitted.