fdt_support: Use CONFIG_NR_DRAM_BANKS if defined

It appears that there are some cases where we have more than 4 banks
of memory.  Use CONFIG_NR_DRAM_BANKS if it's defined to handle this.
This will take up a little extra stack space (64 bytes extra if we go
up to 8 banks), but that seems OK.

Signed-off-by: Doug Anderson <dianders@chromium.org>

common/fdt_support.c

@@ -387,7 +387,11 @@ static void write_cell(u8 *addr, u64 val, int size)
 	}
 }
 
+#ifdef CONFIG_NR_DRAM_BANKS
+#define MEMORY_BANKS_MAX CONFIG_NR_DRAM_BANKS
+#else
 #define MEMORY_BANKS_MAX 4
+#endif
 int fdt_fixup_memory_banks(void *blob, u64 start[], u64 size[], int banks)
 {
 	int err, nodeoffset;