mmc: sdhci: Correct the tuning command handle for PIO mode

mmc: sdhci: Correct the tuning command handle for PIO mode

If sdhci use PIO mode, and use mmc_send_tuning() to send the tuning
command, system will stuck because of the storm irq of sdhci. For PIO mode,
use mmc_send_tuning(), it will trigger buffer_read_ready interrupt and data
transfer complete interrupt.  In current code logic, it will directly
return in sdhci_data_irq, can not call the sdhci_transfer_pio(). So the
buffer_read_ready interrupt storm happen. So for standard tuning method,
need to exclude this case.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/1628858041-1911-1-git-send-email-haibo.chen@nxp.com
[Ulf: Dropped redundant parenthesis in an expression]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>