mmc: am654_sdhci: Add itap_del_ena[] to store itapdlyena bit

Set itap_del_ena if ITAPDLY is found in DT or if the tuning
algorithm was executed and found the optimal ITAPDLY. Add the
functionality to save ITAPDLYENA that can be referenced later
by storing the bit in array itap_del_ena[].

Signed-off-by: Judith Mendez <jm@ti.com>