tools: add sub-dir modules in unit-test related checks

It is possible to have similar modules under a directory.
Hence, add to unit test related checks the possibility to have multiple
levels under module folder

Signed-off-by: Mohamed Omar Asaker <mohamed.omarasaker@arm.com>
Change-Id: I75513f75e9c28763abc21ce182e8d73cde0cd0b2