lvgl: add customize compilation optimization level config

Signed-off-by: pengyiqiang <[email protected]>

Author: pengyiqiang

graphics/lvgl/Kconfig

@@ -1641,4 +1641,8 @@ menu "LVGL configuration"
 
 endmenu
 
+config LV_OPTLEVEL
+	string "Customize compilation optimization level"
+	default ""
+
 endif # GRAPHICS_LVGL

graphics/lvgl/Makefile

@@ -78,6 +78,11 @@ ifeq ($(wildcard $(LVGL_UNPACKNAME)/.git),)
 context:: $(LVGL_UNPACKNAME)
 endif
 
+ifneq ($(CONFIG_LV_OPTLEVEL), "")
+CFLAGS   += $(CONFIG_LV_OPTLEVEL)
+CXXFLAGS += $(CONFIG_LV_OPTLEVEL)
+endif
+
 include $(APPDIR)/Application.mk
 
 ifeq ($(wildcard $(LVGL_UNPACKNAME)/.git),)