SCSI cdrom support cannot be configured as a module because sr_mod.o then has a unresolved reference to req_finished_io. This function is unique to pinstripe, I could not find it in the regular kernel sources. You have simply neglected to export the symbol for use by modules, because it does get resolved if scsi cdrom support is compiled into the kernel (as is done for the distribution kernel).
*** This bug has been marked as a duplicate of 16174 ***