[U-Boot] CPU Wachtog for P2041

[Rainer Boschung]

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