mmcsd_sdio: Arm the write complete detection

The Multiblock write path was missing the
   the SDIO_WAITENABLE with SDIOWAIT_WRCOMPLETE.

   This could be seen with debugging turned on as

   mmcsd_eventwait: ERROR: Awakened with 10
   mmcsd_transferready: ERROR: mmcsd_eventwait for transfer ready failed: -5

drivers/mmcsd/mmcsd_sdio.c

@@ -2077,6 +2077,12 @@ static ssize_t mmcsd_writemultiple(FAR struct mmcsd_state_s *priv,
 
   priv->wrbusy = true;
 
+#if defined(CONFIG_MMCSD_SDIOWAIT_WRCOMPLETE)
+  /* Arm the write complete detection with timeout */
+
+  SDIO_WAITENABLE(priv->dev, SDIOWAIT_WRCOMPLETE | SDIOWAIT_TIMEOUT);
+#endif
+
   /* On success, return the number of blocks written */
 
   return nblocks;