net: ethernet: ti: cpsw_ale: use regfields for ALE registers

Map the entire ALE registerspace using regmap.

Add regfields for Major and Minor Version fields.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>