[conf] force using gps_ublox module instead of subsystem

conf/firmwares/subsystems/shared/gps_ublox.makefile

@@ -1,44 +1 @@
-# Hey Emacs, this is a -*- makefile -*-
+$(error Error: The gps ublox subsystem has been converted to a module, replace <subsystem name="gps" type="ublox"/> by <module name="gps" type="ublox"/>)
-# UBlox LEA
-
-GPS_LED ?= none
-UBX_GPS_PORT ?= $(GPS_PORT)
-UBX_GPS_BAUD ?= $(GPS_BAUD)
-
-UBX_GPS_PORT_LOWER=$(shell echo $(UBX_GPS_PORT) | tr A-Z a-z)
-
-ap.CFLAGS += -DUSE_GPS -DUBX
-ap.CFLAGS += -DUBX_GPS_LINK=$(UBX_GPS_PORT_LOWER)
-ap.CFLAGS += -DUSE_$(UBX_GPS_PORT)
-ap.CFLAGS += -D$(UBX_GPS_PORT)_BAUD=$(UBX_GPS_BAUD)
-
-ifneq ($(GPS_LED),none)
-  ap.CFLAGS += -DGPS_LED=$(GPS_LED)
-endif
-
-ifdef SECONDARY_GPS
-ifneq (,$(findstring $(SECONDARY_GPS), ublox))
-# this is the secondary GPS
-ap.CFLAGS += -DGPS_SECONDARY_TYPE_H=\"subsystems/gps/gps_ubx.h\"
-ap.CFLAGS += -DSECONDARY_GPS=gps_ubx
-else
-ap.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_ubx.h\"
-ap.CFLAGS += -DPRIMARY_GPS=gps_ubx
-endif
-else
-# plain old single GPS usage
-ap.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_ubx.h\"
-endif
-
-ap.srcs += $(SRC_SUBSYSTEMS)/gps/gps_ubx.c
-ap.srcs += $(SRC_SUBSYSTEMS)/gps.c
-
-sim.CFLAGS += -DUSE_GPS
-sim.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_sim.h\"
-sim.srcs += $(SRC_SUBSYSTEMS)/gps/gps_sim.c
-sim.srcs += $(SRC_SUBSYSTEMS)/gps.c
-
-nps.CFLAGS += -DUSE_GPS
-nps.CFLAGS += -DGPS_TYPE_H=\"subsystems/gps/gps_sim_nps.h\"
-nps.srcs += $(SRC_SUBSYSTEMS)/gps/gps_sim_nps.c
-nps.srcs += $(SRC_SUBSYSTEMS)/gps.c