mmc: dw_mmc: miscaculated the fifo-depth with wrong bit operation

In FIFOTH register, the RX_WMark field (bits[27:16]) defaults to
FIFO_DEPTH - 1. When reading it, bits[26:16] were being used, so
fix it to use the mask 0xfff instead of 0x7ff.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NChris Ball <cjb@laptop.org>

drivers/mmc/host/dw_mmc.c

@@ -1949,7 +1949,7 @@ static int dw_mci_probe(struct platform_device *pdev)
 		 * should put it in the platform data.
 		 */
 		fifo_size = mci_readl(host, FIFOTH);
-		fifo_size = 1 + ((fifo_size >> 16) & 0x7ff);
+		fifo_size = 1 + ((fifo_size >> 16) & 0xfff);
 	} else {
 		fifo_size = host->pdata->fifo_depth;
 	}