mmc: core: Fix use of uninitialized data in mmc_cmd_app.

mmc_cmd_app did not zero out mmc_command on stack.
Reported-by: NChuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: NAndrei Warkentin <andreiw@motorola.com>
Signed-off-by: NChris Ball <cjb@laptop.org>

drivers/mmc/core/sd_ops.c

@@ -29,6 +29,8 @@ static int mmc_app_cmd(struct mmc_host *host, struct mmc_card *card)
 	BUG_ON(!host);
 	BUG_ON(card && (card->host != host));
 
+	memset(&cmd, 0, sizeof(struct mmc_command));
+
 	cmd.opcode = MMC_APP_CMD;
 
 	if (card) {