dm: spl: mmc: Support raw partitions with CONFIG_BLK

Fix up the call in mmc_load_image_raw_partition() to use the correct
function to obtain the MMC device, so that this code can support driver
model.
Signed-off-by: NSimon Glass <sjg@chromium.org>

common/spl/spl_mmc.c

@@ -155,7 +155,7 @@ static int mmc_load_image_raw_partition(struct mmc *mmc, int partition)
 	disk_partition_t info;
 	int err;
 
-	err = part_get_info(&mmc->block_dev, partition, &info);
+	err = part_get_info(mmc_get_blk_desc(mmc), partition, &info);
 	if (err) {
 #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
 		puts("spl: partition error\n");