mmcsd: add nxsig_usleep delay after MMC_CMD1 command

MMC_CMD1 command is used to check whether card is MMC type (checked if
CONFIG_MMCSD_MMCSUPPORT is enabled). This commit inserts nxsig_usleep
wait if this check fails. This is to ensure the communication recovers
from invalid response as this may take some time on some platforms (
samv7 for example). Following command for SDHC check may fail if sleep
is not used.

Signed-off-by: Michal Lenc <michallenc@seznam.cz>

drivers/mmcsd/mmcsd_sdio.c

@@ -3377,6 +3377,12 @@ static int mmcsd_cardidentify(FAR struct mmcsd_state_s *priv)
   if (ret != OK)
     {
       ferr("ERROR: CMD1 RECVR3: %d\n", ret);
+
+      /* CMD1 did not succeed, card is not MMC. This sleep let
+       * the communication to recover before another send.
+       */
+
+      nxsig_usleep(MMCSD_IDLE_DELAY);
     }
   else
     {