mk: fixed F4Light build scripts

mk/board_F4Light.mk

@@ -1,5 +1,3 @@
-
-#TOOLCHAIN = NATIVE
 TOOLCHAIN = ARM
 
 ARM_CXX     :=  arm-none-eabi-g++
@@ -88,7 +86,7 @@ include $(BOARDS_PATH)/$(BOARD)/target-config.mk
 
 EXTRAFLAGS += -DHAVE_STD_NULLPTR_T=0  -DHAVE_BYTESWAP_H=0
 EXTRAFLAGS += $(SKETCHLIBINCLUDES) -DARDUPILOT_BUILD -DTESTS_MATHLIB_DISABLE  -DSKETCH_MAIN=ArduPilot_main
-GITFLAGS   := -DGIT_VERSION="\"$(GIT_VERSION) $(shell date --rfc-3339=seconds)\""
+GITFLAGS   := -DGIT_VERSION="\"$(GIT_VERSION) $(shell date --rfc-3339=date)\""
 
 
 #-Werror

mk/help.mk

@@ -30,4 +30,4 @@ help:
 	@echo "  vrbrain - the VRBrain boards"
 	@echo "  sitl - the SITL Software In The Loop simulation"
 	@echo "  qflight - qualcomm flight board"
-	@echo "  f4light - the OpenPilot Revolution Mini"
+	@echo "  f4light - the OpenPilot Revolution, Revolution Mini, AirbotF4 and similar boards"