mmc: sdhci_am654: Add retry tuning

mmc: sdhci_am654: Add retry tuning

Add retry tuning up to 10 times if we fail to find
a failing region or no passing itapdly. This is
necessary since some eMMC has been observed to never
find a failing itapdly on the first couple of tuning
iterations, but eventually does. Keep count of current
tuning iteration using tuning_loop. It has been observed
that the tuning algorithm does not need to loop more
than 10 times before finding a failing itapdly.

Signed-off-by: Judith Mendez <jm@ti.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20240904232512.830778-2-jm@ti.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>