logging: workaround hard fault on Cortex-M0 with sys-t/catalog.

For some reason, running sys-t with catalog message on
Cortex-M0 would result in hard fault in mipi_catalog_formatter()
if log_output_syst.c is complied before the backends (and weird
enough, only with SIZE optimization). This new ordering was
introduced in commit f5587552
as it was to group all backend source files under a single
directory.

Workaround the issue by compiling file later after backends
as this issue is causing CI failures. Actual root-cause is TBD.

Relates #50941

Signed-off-by: Daniel Leung <daniel.leung@intel.com>