SD/MMC: check the card status during erase operation

Use the function 'mmc_send_status' to check the card status.
only when the card is ready, driver can send the next erase command
to the card, otherwise, the erase will failed:
=> mmc erase 0 1
MMC erase: dev # 0, block # 0, count 1 ... 1 blocks erase: OK
=> mmc erase 0 2
MMC erase: dev # 0, block # 0, count 2 ... mmc erase failed
1 blocks erase: ERROR
=> mmc erase 0 4
MMC erase: dev # 0, block # 0, count 4 ... mmc erase failed
1 blocks erase: ERROR

Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
CC: Andy Fleming <afleming@gmail.com>
CC: Marek Vasut <marex@denx.de>
Signed-off-by: Andy Fleming <afleming@freescale.com>

drivers/mmc/mmc.c

@@ -333,6 +333,7 @@ mmc_berase(int dev_num, unsigned long start, lbaint_t blkcnt)
 	int err = 0;
 	struct mmc *mmc = find_mmc_device(dev_num);
 	lbaint_t blk = 0, blk_r = 0;
+	int timeout = 1000;
 
 	if (!mmc)
 		return -1;
@@ -352,6 +353,10 @@ mmc_berase(int dev_num, unsigned long start, lbaint_t blkcnt)
 			break;
 
 		blk += blk_r;
+
+		/* Waiting for the ready status */
+		if (mmc_send_status(mmc, timeout))
+			return 0;
 	}
 
 	return blk;