Fix some bugs in TRAB board flash driver.

- increase CFG_FLASH_ERASE_TOUT from 2 to 15 seconds
- use CFG_FLASH_WRITE_TOUT for programming instead of CFG_FLASH_ERASE_TOUT
- remove "Unlock Bypass" mode, because macronix flashes do not support
  this mode officially
- fix flash reset command from 0x00FF to 0x00F0. 0x00FF is only specified
  for Intel compatible flashes, not for AMD compatible.
Patch by Martin Krause, 15 Feb 2006