Clean up makefiles

Change-Id: I76f1909565905e1c07f44c1660d24d806f94c95e
wpan: fix build issues

- Remove refernce to non existent files in ti-wpan-products.mk
- Include wpan components only for TI builds

Signed-off-by: Vishal Mahaveer <vishalm@ti.com>
Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: Id731c538f814ff9ab296c0bae19deaf58ed03b7e
wpan: Enable flag check for FM app

Some devices need to provide a modified version of the FM app

Change-Id: Ie7aeefc63ba9e81f1027fb33b2b28678880d36ab