Fixes in trace refactoring

- Deprecates ATAMSG
- trace_ext.c is arm32 specific
- tee_kta_trace.h and trace_ta.h are generic
- Default level is now 1 (was 2)

Signed-off-by: Pascal Brand <pascal.brand@st.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>