Please list the birth date of the player who has won the most MVPs.
won the most MVP refers to Max(Count(award = 'Most Valuable Player'))
SELECT T1.birthDate FROM players AS T1 INNER JOIN awards_players AS T2 ON T1.playerID = T2.playerID WHERE T2.award = 'Most Valuable Player' GROUP BY T1.playerID, T1.birthDate ORDER BY COUNT(award) DESC LIMIT 1