Trace use scope macro instead of begin-end

Since we don't need to follow functions usecase,
use trace scope macro instead of begin-end

+

DALI_TRACE_FUNCTION can send tag as NULL
if ENABLE_DEBUG is not defined.
To avoid this case, let we nullcheck for trace tag.
(Note, trace-manager-impl-generic already consider NULL tag)

Change-Id: I55177bbcac344abde42d5afe7cc807114f027a39
Signed-off-by: Eunki Hong <eunkiki.hong@samsung.com>