mmc: moxart: fix return value check of mmc_add_host()

mmc_add_host() may return error, if we ignore its return value, the memory
that allocated in mmc_alloc_host() will be leaked and it will lead a kernel
crash because of deleting not added device in the remove path.

So fix this by checking the return value and goto error path which will call
mmc_free_host().

Fixes: 1b66e94e ("mmc: moxart: Add MOXA ART SD/MMC driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20221101063023.1664968-3-yangyingliang@huawei.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/moxart-mmc.c

@@ -665,7 +665,9 @@ static int moxart_probe(struct platform_device *pdev)
 		goto out;
 
 	dev_set_drvdata(dev, mmc);
-	mmc_add_host(mmc);
+	ret = mmc_add_host(mmc);
+	if (ret)
+		goto out;
 
 	dev_dbg(dev, "IRQ=%d, FIFO is %d bytes\n", irq, host->fifo_width);