libstb_hal: Suppress implicit-fallthrough warnings from GCC 7

libdvbci/dvbci_camgr.cpp

@@ -85,6 +85,7 @@ int eDVBCICAManagerSession::doAction()
 		}
 		case stateFinal:
 			printf("[CI CA] stateFinal and action should not happen\n");
+			// fall through
 		default:
 			return 0;
 	}

libdvbci/dvbci_ccmgr.cpp

@@ -1339,6 +1339,7 @@ int eDVBCIContentControlManagerSession::doAction()
 		}
 		case stateFinal:
 			printf("stateFinal und action! kann doch garnicht sein ;)\n");
+			// fall through
 		default:
 			return 0;
 	}

libdvbci/dvbci_datetimemgr.cpp

@@ -52,6 +52,7 @@ int eDVBCIDateTimeSession::doAction()
 			return 0;
 		case stateFinal:
 			printf("stateFinal und action! kann doch garnicht sein ;)\n");
+			// fall through
 		default:
 			return 0;
 	}

libdvbci/dvbci_session.cpp

@@ -179,11 +179,12 @@ eDVBCISession* eDVBCISession::createSession(eDVBCISlot *slot, const unsigned cha
 				printf("[CI SESS] CC MANAGER\n");
 				sessions[session_nb - 1] = new eDVBCIContentControlManagerSession(slot);
 				break;
-		}
+		} // fall through
 		case 0x00100041:
 //			session=new eDVBCIAuthSession;
 			printf("[CI SESS] AuthSession\n");
 //			break;
+		  // fall through
 		case 0x00200041:
 		default:
 			printf("[CI SESS] unknown resource type %02x %02x %02x %02x\n", resource_identifier[0], resource_identifier[1], resource_identifier[2], resource_identifier[3]);