legoev3: Migrate to DM_I2C

Perform a basic migration of the calls in setup_serial_number() to DM so
that we can switch to using DM_I2C on this platform.

Cc: David Lechner <david@lechnology.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Acked-by: David Lechner <david@lechnology.com>
2 files changed