mmc: dw_mmc: transfer proper bytes to FIFO

The former implement, dw_mmc will push and pop the redundant data to
FIFO, we should transfer it according to the real size.

Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
index a6a5fc6..a0a582b 100644
--- a/drivers/mmc/dw_mmc.c
+++ b/drivers/mmc/dw_mmc.c
@@ -125,6 +125,7 @@
 					len = dwmci_readl(host, DWMCI_STATUS);
 					len = (len >> DWMCI_FIFO_SHIFT) &
 						    DWMCI_FIFO_MASK;
+					len = min(size, len);
 					for (i = 0; i < len; i++)
 						*buf++ =
 						dwmci_readl(host, DWMCI_DATA);
@@ -138,6 +139,7 @@
 					len = fifo_depth - ((len >>
 						   DWMCI_FIFO_SHIFT) &
 						   DWMCI_FIFO_MASK);
+					len = min(size, len);
 					for (i = 0; i < len; i++)
 						dwmci_writel(host, DWMCI_DATA,
 							     *buf++);