[regression, bisected] no MMC on rk3399-gru-kevin with 5.10-rc1

[Vicente Bergas]

Hi,
commit 21b2cec61c04bd175f0860d9411a472d5a0e7ba1
mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.4
broke booting rk3399-gru-kevin.

The kernel waits forever for the root device to appear on MMC.
Removing the line containing PROBE_PREFER_ASYNCHRONOUS in
drivers/mmc/host/dw_mmc-rockchip.c fixes the issue.

Regards,
  Vicente.