rockchip: Makefile: streamline SPL/TPL configuration

Handling TPL and SPL in the Makefile for mach-rockchip was based on
nested if checks and/or if-else-if paths.  This can be simplified and
made more readable by using $(SPL_TPL_) and by introducing
intermediate variables for the aggregation of SPL and TPL features.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/mach-rockchip/Makefile

@@ -4,37 +4,47 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-obj-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o
-obj-$(CONFIG_$(SPL_TPL_)RAM) += sdram_common.o
+# We don't want the bootrom-helper present in a full U-Boot build, as
+# this may have entered from ATF with the stack-pointer pointing to
+# inaccessible/protected memory (and the bootrom-helper assumes that
+# the stack-pointer is valid before switching to the U-Boot stack).
+obj-spl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o save_boot_param.o
+obj-tpl-$(CONFIG_ROCKCHIP_BROM_HELPER) += bootrom.o save_boot_param.o
+
+obj-tpl-$(CONFIG_ROCKCHIP_RK3188) += rk3188-board-tpl.o
+
+obj-spl-$(CONFIG_ROCKCHIP_RK3036) += rk3036-board-spl.o
+obj-spl-$(CONFIG_ROCKCHIP_RK3188) += rk3188-board-spl.o
+obj-spl-$(CONFIG_ROCKCHIP_RK322X) += rk322x-board-spl.o
+obj-spl-$(CONFIG_ROCKCHIP_RK3288) += rk3288-board-spl.o
+obj-spl-$(CONFIG_ROCKCHIP_RK3368) += rk3368-board-spl.o
+obj-spl-$(CONFIG_ROCKCHIP_RK3399) += rk3399-board-spl.o
 
-ifdef CONFIG_TPL_BUILD
-obj-$(CONFIG_ROCKCHIP_RK3188) += rk3188-board-tpl.o
-obj-$(CONFIG_ROCKCHIP_BROM_HELPER) += save_boot_param.o
-else ifdef CONFIG_SPL_BUILD
-obj-$(CONFIG_ROCKCHIP_RK3036) += rk3036-board-spl.o
-obj-$(CONFIG_ROCKCHIP_RK3188) += rk3188-board-spl.o
-obj-$(CONFIG_ROCKCHIP_RK322X) += rk322x-board-spl.o
-obj-$(CONFIG_ROCKCHIP_RK3288) += rk3288-board-spl.o
-obj-$(CONFIG_ROCKCHIP_RK3399) += rk3399-board-spl.o
-obj-$(CONFIG_ROCKCHIP_BROM_HELPER) += save_boot_param.o
-else
+ifeq ($(CONFIG_SPL_BUILD)$(CONFIG_TPL_BUILD),)
 obj-$(CONFIG_ROCKCHIP_RK3188) += rk3188-board.o
 obj-$(CONFIG_ROCKCHIP_RK322X) += rk322x-board.o
 obj-$(CONFIG_ROCKCHIP_RK3288) += rk3288-board.o
 obj-$(CONFIG_ROCKCHIP_RK3036) += rk3036-board.o
 endif
+
+obj-$(CONFIG_$(SPL_TPL_)RAM) += sdram_common.o
+
 ifndef CONFIG_ARM64
 obj-y += rk_timer.o
 endif
-obj-$(CONFIG_ROCKCHIP_RK3036) += rk3036/
-
-ifndef CONFIG_TPL_BUILD
-obj-$(CONFIG_ROCKCHIP_RK3188) += rk3188/
-endif
 
+obj-$(CONFIG_ROCKCHIP_RK3036) += rk3036/
+obj-tpl-$(CONFIG_ROCKCHIP_RK3188) += rk3188/
 obj-$(CONFIG_ROCKCHIP_RK322X) += rk322x/
 obj-$(CONFIG_ROCKCHIP_RK3288) += rk3288/
 obj-$(CONFIG_ROCKCHIP_RK3328) += rk3328/
 obj-$(CONFIG_ROCKCHIP_RK3368) += rk3368/
 obj-$(CONFIG_ROCKCHIP_RK3399) += rk3399/
 obj-$(CONFIG_ROCKCHIP_RV1108) += rv1108/
+
+# Clear out SPL objects, in case this is a TPL build
+obj-spl-$(CONFIG_TPL_BUILD) =
+
+# Now add SPL/TPL objects back into the main build
+obj-$(CONFIG_SPL_BUILD) += $(obj-spl-y)
+obj-$(CONFIG_TPL_BUILD) += $(obj-tpl-y)