mmc: meson-mx-sdio: Set MMC_CAP_WAIT_WHILE_BUSY

The Meson SDIO controller uses the DAT0 lane for hardware busy
detection. Set MMC_CAP_WAIT_WHILE_BUSY accordingly. This fixes
the following error observed with Linux 5.7 (pre-rc-1):
  mmc1: Card stuck being busy! __mmc_poll_for_busy
  blk_update_request: I/O error, dev mmcblk1, sector 17111080 op
   0x3:(DISCARD) flags 0x0 phys_seg 1 prio class 0

Fixes: ed80a13 ("mmc: meson-mx-sdio: Add a driver for the Amlogic Meson8 and Meson8b SoCs")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200416183513.993763-2-martin.blumenstingl@googlemail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/meson-mx-sdio.c

@@ -570,7 +570,7 @@ static int meson_mx_mmc_add_host(struct meson_mx_mmc_host *host)
 	mmc->f_max = clk_round_rate(host->cfg_div_clk,
 				    clk_get_rate(host->parent_clk));
 
-	mmc->caps |= MMC_CAP_ERASE | MMC_CAP_CMD23;
+	mmc->caps |= MMC_CAP_ERASE | MMC_CAP_CMD23 | MMC_CAP_WAIT_WHILE_BUSY;
 	mmc->ops = &meson_mx_mmc_ops;
 
 	ret = mmc_of_parse(mmc);