out waiting for hardware interrupt.
  mmcblk0: error -110 transferring data, sector 3678224, nr 40, cmd response 0x900, card status 0xc00
  end_request: I/O error, dev mmcblk0, sector 3678225
  Buffer I/O error on device mmcblk0p1, logical block 458754
  lost page write due to I/O error on mmcblk0p1

This patch fixes the problem by lowering the usdhc clock and correcting
watermark configuration.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Chris Ball <cjb@laptop.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
dQ