M68K: eb_cpu5282: general update and enhanced board support

- update clock settings for higher perfomance
- change standard baud rate to 115200
- fix flash base address
- remove unused defines
- add I2C support
- switch form board dependent flash to cfi
- remove board dependent flash code
- use sdram bank 0 instead of bank 1 on boot
- enable on board frame buffer instead external
- remove fake mac address form config
- add watchdog support
- add status led support

Signed-off-by: Jens Scharsig (BuS Elektronik) <esw@bus-elektronik.de>
[agust: fixed small style issues and build warning]
Signed-off-by: Anatolij Gustschin <agust@denx.de>