uboot-phytec

mmc: add additional quirk for APP_CMD retry

It was observed (on ClearFog Base) that sending MMC APP_CMD returned
an error on the first attempt. The issue appears to be timing related
since even inserting a puts() short debug entry before the execution
added sufficient delay to receive success on first attempt.

Follow the existing quirks pattern to retry if initial issuance
failed so as to not introduce any delay unless needed.

Signed-off-by: Joel Johnson <mrjoel@lixil.net>