RANAP: Split FormatInformationParameter / SDUParameterItem

The definition of the above data types as per 3GPP specs results in a
SEQUENCE_OF() an anonymous structure, which is slightly inconvenient to
use.  So let's split the SEQUENCE OF part and the actual definition of
the item in separate types.
diff --git a/src/ranap_common.h b/src/ranap_common.h
index 599d912..9c1945f 100644
--- a/src/ranap_common.h
+++ b/src/ranap_common.h
@@ -475,7 +475,9 @@
 #include "ranap/RANAP_SAPI.h"
 #include "ranap/RANAP_SDU-ErrorRatio.h"
 #include "ranap/RANAP_SDU-FormatInformationParameters.h"
+#include "ranap/RANAP_SDU-FormatInformationParameterItem.h"
 #include "ranap/RANAP_SDU-Parameters.h"
+#include "ranap/RANAP_SDU-ParameterItem.h"
 #include "ranap/RANAP_SNA-Access-Information.h"
 #include "ranap/RANAP_SNAC.h"
 #include "ranap/RANAP_SRB-ID.h"