Move xnap lib back to openair2/XNAP/

Remove the ITTI header, because it would trigger compilation errors (we
don't link in LTE/NR RRC headers), but we don't actually need it.

openair2/XNAP/CMakeLists.txt

@@ -1,6 +1,9 @@
 add_subdirectory(lib)
 add_subdirectory(MESSAGES)
 
+add_library(xnap xnap_common.c)
+target_link_libraries(xnap PUBLIC asn1_xnap xnap_lib)
+
 if(ENABLE_TESTS)
   add_subdirectory(tests)
 endif()

openair2/XNAP/xnap_common.h

@@ -25,7 +25,6 @@
 #define XNAP_COMMON_H_
 
 #include "XNAP_XnAP-PDU.h"
-#include "intertask_interface.h"
 #include "common/openairinterface5g_limits.h"
 #include "oai_asn1.h"
 #include "XNAP_ProtocolIE-Field.h"