Can you charm an enemy unit from one battlefield to the other if it doesn't have ganking?

Yes, you can use Charm to move an enemy unit from one battlefield to another, even if that unit does not have the Ganking keyword.

According to the official rulings for Charm:

• Ganking restrictions (which limit how units perform a "Standard Move") do not apply to movement caused by spells or abilities.
• Because Charm is a spell effect and not a "Standard Move," it is not restricted by the Ganking requirement.
• When you use Charm to move an enemy unit to your battlefield, that unit is considered to be attacking for the purposes of combat.