hw/nand.c: Fix nand erase operation

Usually, nand erase operation has only 2 or 3 address cycles.
We need to mask s->addr to zero unset stale high-order bytes in the nand address
before using it as the erase address.

This fixes the NAND erase operation in Linux.

[PC: Generalised to work for any number of address cycles rather than just 3]
Signed-off-by: NWendy Liang <jliang@xilinx.com>
Signed-off-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: 1364967188-26711-1-git-send-email-peter.crosthwaite@xilinx.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/nand.c

@@ -297,6 +297,7 @@ static void nand_command(NANDFlashState *s)
         break;
 
     case NAND_CMD_BLOCKERASE2:
+        s->addr &= (1ull << s->addrlen * 8) - 1;
         if (nand_flash_ids[s->chip_id].options & NAND_SAMSUNG_LP)
             s->addr <<= 16;
         else