mmc: sdhci-esdhc-imx: optimize the strobe dll setting

After set the STROBE SLV delay target value, it need to wait some
time to let the usdhc lock the REF and SLV clock. In normal case,
1~2us is enough for imx8/imx6 and imx7d, and 4~5us is enough for
imx7ulp, but when do reboot stress test or do the bind/unbind stress
test, sometimes need to wait about 10us to get the status lock.

This patch optimize delay handle method, only print the warning
message if the status is still not lock after 1ms delay.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/1582100757-20683-3-git-send-email-haibo.chen@nxp.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>