Revamp the iop3xx board support: move the support code for each iop
board type into its own file, start using platform serial and platform
physmap flash devices, switch to a per-board time tick rate, and get
rid of the ARCH_EP80219 and STEPD config options by doing the relevant
checks at run time.
Signed-off-by: Lennert Buytenhek
Signed-off-by: Russell King