Fix 'make clean' in STM model-specific subfolders

blinky_test/Makefile

@@ -7,6 +7,6 @@ OBJS += util.o
 OBJS += console.o
 OBJS += string.o
 
-SUBDIRS += $(stm32)
+SUBDIRS += f1
 
 console.o: CFLAGS += -DBAUD=115200

bootloader/Makefile

@@ -14,7 +14,8 @@ OBJS += util.o
 OBJS-$(debug) += console.o
 
 SUBDIRS += usb
-SUBDIRS += $(stm32)
+SUBDIRS-$(stm32f1) += f1
+SUBDIRS-$(stm32f7) += f7
 
 .PHONY: $(RPATH)/build_info.c
 build_info.o: CFLAGS += -DFW_MAJOR=$(FW_MAJOR) -DFW_MINOR=$(FW_MINOR)

src/Makefile

@@ -13,7 +13,8 @@ OBJS += floppy.o
 OBJS-$(debug) += console.o
 
 SUBDIRS += usb
-SUBDIRS += $(stm32)
+SUBDIRS-$(stm32f1) += f1
+SUBDIRS-$(stm32f7) += f7
 
 .PHONY: build_info.c
 build_info.o: CFLAGS += -DFW_MAJOR=$(FW_MAJOR) -DFW_MINOR=$(FW_MINOR)