Revert "fdt_support: Use CONFIG_NR_DRAM_BANKS if defined"

This reverts commit 5e5745465c.

The reverted commit didn't support the scenario where there are less
DRAM banks in U-Boot than in Linux.
Also, it didn't introduce any new functionality, only limitaion.
User could just increase MEMORY_BANKS_MAX if it's too small.
Reviewed-by: Simon Glass <sjg@chromium.org>

common/fdt_support.c

@@ -409,11 +409,7 @@ static int fdt_pack_reg(const void *fdt, void *buf, u64 *address, u64 *size,
 	return p - (char *)buf;
 }
 
-#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;