pgw: add missing BSSGP_EncDec.cc

Fix for:
/usr/bin/ld: BSSGP_Types_part_4.so: undefined reference to `BSSGP__Types::dec__PDU__BSSGP(OCTETSTRING const&)'
/usr/bin/ld: Osmocom_Gb_Types.so: undefined reference to `BSSGP__Types::enc__PDU__BSSGP(BSSGP__Types::PDU__BSSGP const&)'

Related: OS#5252
Change-Id: I010df10396d264e67bd8c712daafcfb79262ece2
diff --git a/pgw/regen_makefile.sh b/pgw/regen_makefile.sh
index 65954c5..21f03ba 100755
--- a/pgw/regen_makefile.sh
+++ b/pgw/regen_makefile.sh
@@ -2,6 +2,7 @@
 
 FILES="
 	*.ttcn
+	BSSGP_EncDec.cc
 	DIAMETER_CodecPort_CtrlFunctDef.cc
 	DIAMETER_EncDec.cc
 	GTPC_EncDec.cc