replacing umlaute and fixing address in headers Haldeneggsteig -> Universitaetsstrasse

Signed-off-by: Reto Achermann <reto.achermann@inf.ethz.ch>

kernel/logging: Convert defined constants to enum

Signed-off-by: Moritz Hoffmann <moritz.hoffmann@inf.ethz.ch>

kernel/logging: Change default log level to LOG_NOTE

The previous default was LOG_DEBUG with an incorrect level check on the
kernel debug macro.

Signed-off-by: Moritz Hoffmann <moritz.hoffmann@inf.ethz.ch>

kernel: Unify kernel logging infrastructure

Previously, it was part of the infamous misc.c file found in arch-specific
code.

Signed-off-by: Moritz Hoffmann <moritz.hoffmann@inf.ethz.ch>