[tcp] apply ot-config compile options (#7048)

tcplp uses stdio.h which, for some libc implementations, can depend on
Kconfig defines.

These Kconfig defines can be included through compile options in
ot-config.

Link with ot-config to get the compile options.

Signed-off-by: Sebastian Bøe <[email protected]>

third_party/tcplp/CMakeLists.txt

@@ -44,7 +44,11 @@ target_include_directories(${tcplp_static_target}
         ${CMAKE_CURRENT_SOURCE_DIR}/lib
     PRIVATE
         ${OT_PUBLIC_INCLUDES}
-        $<TARGET_PROPERTY:ot-config,INTERFACE_INCLUDE_DIRECTORIES>
+)
+
+target_link_libraries(${tcplp_static_target}
+    PRIVATE
+        ot-config
 )
 
 # TCPlp calls functions that are defined by the core OpenThread (like