mmc: mmci: Add small comment about reset thread

Put a small comment before assigning IRQ_WAKE_THREAD
telling us what is going on.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Yann Gautier <yann.gautier@foss.st.com>
Cc: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210921143359.1738149-1-linus.walleij@linaro.orgSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mmci.c

@@ -1394,6 +1394,10 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
 	} else if (host->variant->busy_timeout && busy_resp &&
 		   status & MCI_DATATIMEOUT) {
 		cmd->error = -ETIMEDOUT;
+		/*
+		 * This will wake up mmci_irq_thread() which will issue
+		 * a hardware reset of the MMCI block.
+		 */
 		host->irq_action = IRQ_WAKE_THREAD;
 	} else {
 		cmd->resp[0] = readl(base + MMCIRESPONSE0);