mmc: sdhci_am654: Drop lookup for deprecated ti,otap-del-sel

mmc: sdhci_am654: Drop lookup for deprecated ti,otap-del-sel

ti,otap-del-sel has been deprecated since v5.7 and there are no users of
this property and no documentation in the DT bindings either.
Drop the fallback code looking for this property, this makes
sdhci_am654_get_otap_delay() much easier to read as all the TAP values
can be handled via a single iterator loop.

Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20231122060215.2074799-1-vigneshr@ti.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>