[U-Boot] CPU Wachtog for P2041

I am using the core watchdog of the P2041 on the kmp204x board.

For the watchdog initialization I use the mpc85xx framework and the powerpc register definitions. However, I had to modify both for the following reasons (Patches 1 to 4): -the e500mc register implementation differs from other ppc -the watchdog init function was missing

Additional function was added to the kmp204x board to use the core WD reset in conjunction with the board specific reset controller (Patches 5 to 9): -trigger a core reset flow upon core WD reset request -check for core WD reset occurance and set the reset reason register accordingly.

Regards Rainer