Kbuild: Tools build at TIMO_BASE directory.

This commit allows the tools build to be executed at TIMO_BASE
directory insted of being executed at the PROJECT_BASE.
This allows the sanity checks to run faster because there is no
need to recompile the tools with every test.

Change-Id: I9e9ac78695db884b44e2693029e9ea6ed96b21c8
Signed-off-by: Juan Manuel Cruz <juan.m.cruz.alcaraz@linux.intel.com>