Retire obsolete or unused headers
Detail: Remove internal use svcdebug.h (moved to Internet component). Remove 4x headers, RISC iX vestiges of podule ("eXpansion Card Bus") support. Admin: Submission for TCP/IP bounty.
Detail: Remove internal use svcdebug.h (moved to Internet component). Remove 4x headers, RISC iX vestiges of podule ("eXpansion Card Bus") support. Admin: Submission for TCP/IP bounty.