uboot-lantiq: danube: fix SPL boot

On danube we only have 0x6800 bytes of usable SRAM. Everything behind
can't be written to and a SPL u-boot locks up during boot.

Since it's a hard to debug issue and took me more than two years to fix
it, I consider it worth to include fix albeit SPL u-boots are not build
in OpenWrt.

I faced the issue while trying to shrink the u-boot to 64K since some
boards only have an u-boot partition of that size from the days
ifx-uboot was used.

Signed-off-by: Mathias Kresin <dev@kresin.me>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

package/boot/uboot-lantiq/patches/0032-MIPS-lantiq-danube-fix-SPL-boot.patch

@@ -0,0 +1,34 @@
+From 65f1f160139c2bac83650c9c7c4aee4e5fd74c7c Mon Sep 17 00:00:00 2001
+From: Mathias Kresin <dev@kresin.me>
+Date: Sun, 2 May 2021 02:03:05 +0200
+Subject: [PATCH] MIPS: lantiq: danube: fix SPL boot
+
+On danube we only have 0x6800 bytes of usable SRAM. Everything behind
+can't be written to and a SPL u-boot locks up during boot.
+
+Signed-off-by: Mathias Kresin <dev@kresin.me>
+Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
+---
+ arch/mips/include/asm/arch-danube/config.h | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/arch/mips/include/asm/arch-danube/config.h
++++ b/arch/mips/include/asm/arch-danube/config.h
+@@ -61,7 +61,7 @@
+ 
+ /* SRAM */
+ #define CONFIG_SYS_SRAM_BASE		0xBE1A0000
+-#define CONFIG_SYS_SRAM_SIZE		0x10000
++#define CONFIG_SYS_SRAM_SIZE		0x6800
+ 
+ /* ASC/UART driver and console */
+ #define CONFIG_LANTIQ_SERIAL
+@@ -117,7 +117,7 @@
+ #define CONFIG_CMD_NET
+ #endif
+ 
+-#define CONFIG_SPL_MAX_SIZE		(32 * 1024)
++#define CONFIG_SPL_MAX_SIZE		(18 * 1024)
+ #define CONFIG_SPL_BSS_MAX_SIZE		(8 * 1024)
+ #define CONFIG_SPL_STACK_MAX_SIZE	(8 * 1024)
+ #define CONFIG_SPL_MALLOC_MAX_SIZE	(32 * 1024)