- corvus board fix problems with toshiba nand chips
  on the corvus board problems with toshiba chips
  Manufacturer ID: 0x98 Chip ID: 0xdc encounterd.

  Solve this in the following way:
  - set other nand timings
  - enable CONFIG_SYS_NAND_READY_PIN

- correct the MACH_TYPE setting

Signed-off-by: Heiko Schocher <hs@denx.de>