[core/sched/cbs] [DEBUG] Add printk base tracing

This patch adds some printk based log events which could be conditonally
compiled to support scheduler understanding and debugging.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>
[core/sched/cbs] [DEBUG] Remove static methods to support debugging

GCC inline static methods which have a single call in the compilation
unit, which makes sometimes harder the debugging. This patch remove
all the static modifiers to improve debugging while the scheduler is
in development.

Signed-off-by: Patrick Bellasi <derkling@gmail.com>