spl_nor.c: Support devicetree sizes different from 16k

The devicetrees for various platforms already exceed 16k. Add a define
CONFIG_SYS_FDT_SIZE to specify the FDT size, and set to 16k for the
two boards that define this CONFIG_SYS_FDT_BASE parameter. This
allows platforms with larger devicetree blobs to boot from NOR.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
diff --git a/include/configs/microblaze-generic.h b/include/configs/microblaze-generic.h
index 047e756..e5bf700 100644
--- a/include/configs/microblaze-generic.h
+++ b/include/configs/microblaze-generic.h
@@ -305,6 +305,7 @@
 					 0x60000)
 #define CONFIG_SYS_FDT_BASE		(CONFIG_SYS_FLASH_BASE + \
 					 0x40000)
+#define CONFIG_SYS_FDT_SIZE		(16<<10)
 #define CONFIG_SYS_SPL_ARGS_ADDR	(CONFIG_SYS_TEXT_BASE + \
 					 0x1000000)