tools/rtapp: Update rt-app to add FTrace categories support

This update rt-app to the most recent verison available upstream:

   commit 99a96293ace6 ("Merge pull request #80 from derkling/add-ftrace-categories")

which introduced support to inject ftrace events grouped by categories.

This new support will unlock the possibility to build DataFrame getters for the
performance analysis that better matches other trace events.

Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>