Improve the clock Settings for switching to high speed mode in the SDIO framework.

components/drivers/sdio/sdio.c

@@ -892,7 +892,7 @@ static rt_int32_t sdio_init_card(struct rt_mmcsd_host *host, rt_uint32_t ocr)
 
     if (card->flags & CARD_FLAG_HIGHSPEED) 
     {
-        mmcsd_set_clock(host, 50000000);
+        mmcsd_set_clock(host, card->host->freq_max > 50000000 ? 50000000 : card->host->freq_max);
     }
     else
     {