More cleanup:  - move debug output registration out of walker called function  - add missing param description  - fixed parameter types
More cleanup:
 - move debug output registration out of walker called function
 - add missing param description
 - fixed parameter types

[r22814]

libfirm/libfirm,davidgiven/libfirm,killbug2004/libfirm,MatzeB/libfirm,libfirm/libfirm,libfirm/libfirm,8l/libfirm,davidgiven/libfirm,8l/libfirm,MatzeB/libfirm,killbug2004/libfirm,davidgiven/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,libfirm/libfirm,MatzeB/libfirm,davidgiven/libfirm,8l/libfirm,jonashaag/libfirm,killbug2004/libfirm,jonashaag/libfirm,8l/libfirm,killbug2004/libfirm,MatzeB/libfirm,MatzeB/libfirm,8l/libfirm,killbug2004/libfirm,davidgiven/libfirm,8l/libfirm,davidgiven/libfirm,jonashaag/libfirm,killbug2004/libfirm,8l/libfirm,libfirm/libfirm,jonashaag/libfirm,killbug2004/libfirm,davidgiven/libfirm,MatzeB/libfirm,MatzeB/libfirm