650D:sf_dump stubs

Created originally on Bitbucket by es_as (Espen)

Was already merged in Bitbucket before import, marked as merged by the import user

Found stubs by matching pattern with disassembly from EOSM.

Not sure about SF_flash_size though. How do I confirm this. Just went with 0x800000 since both 700D and EOSM uses this.

Tested dump in qemu. Seems to work.