stm32/Makefile: Remove Wno-attributes for ll_usb HAL file.
This HAL file is now patched so it doesn't have these warnings.
@@ -319,7 +319,6 @@ SRC_HAL = $(addprefix $(HAL_DIR)/Src/stm32$(MCU_SERIES)xx_,\
)
ifeq ($(MCU_SERIES),$(filter $(MCU_SERIES),f4 f7 h7 l4))
-$(BUILD)/$(HAL_DIR)/Src/stm32$(MCU_SERIES)xx_ll_usb.o: CFLAGS += -Wno-attributes
SRC_HAL += $(addprefix $(HAL_DIR)/Src/stm32$(MCU_SERIES)xx_,\
hal_sd.c \
ll_sdmmc.c \
