Blackfin arch: check the EXTBANKS field of the DDRCTL1 register to see if we are using both memory banks

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

arch/blackfin/kernel/setup.c

@@ -700,6 +700,8 @@ static inline int __init get_mem_size(void)
 		case DEVWD_8:  ret *= 2;
 		case DEVWD_16: break;
 	}
+	if ((ddrctl & 0xc000) == 0x4000)
+		ret *= 2;
 	return ret;
 #endif
 	BUG();