rockchip: Use an external TPL binary on RK3588

There is no support to initialize DRAM on RK3588 SoCs using U-Boot TPL
and instead an external TPL binary must be used to generate a bootable
u-boot-rockchip.bin image.

Enable ROCKCHIP_EXTERNAL_TPL by default for RK3588, add build steps for
RK3588 to documentation and clean up CONFIG_BINMAN_FDT options.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Jagan Teki <jagan@edgeble.ai>
diff --git a/arch/arm/mach-rockchip/Kconfig b/arch/arm/mach-rockchip/Kconfig
index 0390431..e5ac58a 100644
--- a/arch/arm/mach-rockchip/Kconfig
+++ b/arch/arm/mach-rockchip/Kconfig
@@ -428,7 +428,7 @@
 
 config ROCKCHIP_EXTERNAL_TPL
 	bool "Use external TPL binary"
-	default y if ROCKCHIP_RK3568
+	default y if ROCKCHIP_RK3568 || ROCKCHIP_RK3588
 	help
 	  Some Rockchip SoCs require an external TPL to initialize DRAM.
 	  Enable this option and build with ROCKCHIP_TPL=/path/to/ddr.bin to
diff --git a/configs/neu6a-io-rk3588_defconfig b/configs/neu6a-io-rk3588_defconfig
index c9b2252..fb1ce4c 100644
--- a/configs/neu6a-io-rk3588_defconfig
+++ b/configs/neu6a-io-rk3588_defconfig
@@ -62,5 +62,4 @@
 CONFIG_BAUDRATE=1500000
 CONFIG_DEBUG_UART_SHIFT=2
 CONFIG_SYSRESET=y
-# CONFIG_BINMAN_FDT is not set
 CONFIG_ERRNO_STR=y
diff --git a/configs/rock-3a-rk3568_defconfig b/configs/rock-3a-rk3568_defconfig
index e753832..af13745 100644
--- a/configs/rock-3a-rk3568_defconfig
+++ b/configs/rock-3a-rk3568_defconfig
@@ -69,5 +69,4 @@
 CONFIG_DEBUG_UART_SHIFT=2
 CONFIG_SYS_NS16550_MEM32=y
 CONFIG_SYSRESET=y
-# CONFIG_BINMAN_FDT is not set
 CONFIG_ERRNO_STR=y
diff --git a/configs/rock5b-rk3588_defconfig b/configs/rock5b-rk3588_defconfig
index f3026c7..6619938 100644
--- a/configs/rock5b-rk3588_defconfig
+++ b/configs/rock5b-rk3588_defconfig
@@ -68,5 +68,4 @@
 CONFIG_DEBUG_UART_SHIFT=2
 CONFIG_DEBUG_UART_ANNOUNCE=y
 CONFIG_SYSRESET=y
-# CONFIG_BINMAN_FDT is not set
 CONFIG_ERRNO_STR=y