Use add_subdirectory() for nfapi/ subdirectory

CMakeLists.txt

@@ -2087,8 +2087,6 @@ add_executable(nr-softmodem
   ${OPENAIR1_DIR}/PHY/TOOLS/phy_scope_interface.c
   )
 
-include(${OPENAIR_DIR}/nfapi/CMakeLists.txt)
-
 target_link_libraries(nr-softmodem PRIVATE
   -Wl,--start-group
   UTIL HASHTABLE SCTP_CLIENT SCHED_LIB SCHED_RU_LIB SCHED_NR_LIB PHY_NR PHY PHY_COMMON PHY_NR_COMMON PHY_RU GTPV1U SECURITY
@@ -2514,6 +2512,7 @@ endif()
 
 add_subdirectory(common)
 add_subdirectory(doc)
+add_subdirectory(nfapi)
 add_subdirectory(openair1)
 add_subdirectory(openair2)
 add_subdirectory(openair3)

nfapi/CMakeLists.txt

-include(${OPENAIR_DIR}/nfapi/oai_integration/aerial/CMakeLists.txt)
\ No newline at end of file
+include(oai_integration/aerial/CMakeLists.txt)