mmc/dw_mmc: Allocate the correct amount of descriptors

This fixes two issues:
 * a descriptor was allocated for every block, while a descriptor can
   take 8 blocks
 * there was an off-by-one error in the descriptor preparation: there
   were two last descriptors, one with length==0

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Andy Fleming <afleming@gmail.com>

drivers/mmc/dw_mmc.c

@@ -72,7 +72,7 @@ static void dwmci_prepare_data(struct dwmci_host *host,
 		dwmci_set_idma_desc(cur_idmac, flags, cnt,
 				start_addr + (i * PAGE_SIZE));
 
-		if(blk_cnt < 8)
+		if (blk_cnt <= 8)
 			break;
 		blk_cnt -= 8;
 		cur_idmac++;
@@ -111,7 +111,7 @@ static int dwmci_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
 {
 	struct dwmci_host *host = (struct dwmci_host *)mmc->priv;
 	ALLOC_CACHE_ALIGN_BUFFER(struct dwmci_idmac, cur_idmac,
-				 data ? data->blocks : 0);
+				 data ? DIV_ROUND_UP(data->blocks, 8) : 0);
 	int flags = 0, i;
 	unsigned int timeout = 100000;
 	u32 retry = 10000;