cmake remove circular linking and reorganize

- px4_add_module now requires MAIN
 - px4_add_library doesn't automatically link

src/drivers/gps/CMakeLists.txt

@@ -44,6 +44,5 @@ px4_add_module(
 		devices/src/ashtech.cpp
 		devices/src/ubx.cpp
 	DEPENDS
-		platforms__common
 		git_gps_devices
 	)

src/drivers/gps/gps.cpp

@@ -72,7 +72,7 @@
 #include <mathlib/mathlib.h>
 #include <systemlib/systemlib.h>
 #include <systemlib/err.h>
-#include <systemlib/param/param.h>
+#include <parameters/param.h>
 #include <drivers/drv_gps.h>
 #include <uORB/uORB.h>
 #include <uORB/topics/vehicle_gps_position.h>