package/uboot: define help commands when using Kconfig

Expose the Kconfig-related help commands when U-Boot uses the Kconfig
configuration. Like others (like Linux, barebox, busybox), only expose
menuconfig, not all the configurators.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

boot/uboot/uboot.mk

@@ -181,6 +181,12 @@ endif # BR2_TARGET_UBOOT_USE_DEFCONFIG
 
 UBOOT_KCONFIG_EDITORS = menuconfig xconfig gconfig nconfig
 UBOOT_KCONFIG_OPTS = $(UBOOT_MAKE_OPTS)
+define UBOOT_HELP_CMDS
+	@echo '  uboot-menuconfig       - Run U-Boot menuconfig'
+	@echo '  uboot-savedefconfig    - Run U-Boot savedefconfig'
+	@echo '  uboot-update-defconfig - Save the U-Boot configuration to the path specified'
+	@echo '                             by BR2_TARGET_UBOOT_CUSTOM_CONFIG_FILE'
+endef
 endif # BR2_TARGET_UBOOT_BUILD_SYSTEM_LEGACY
 
 define UBOOT_BUILD_CMDS