i2c: core: add managed function for adding i2c adapters

i2c: core: add managed function for adding i2c adapters

Some I2C controller drivers will only unregister the I2C
adapter in their .remove() callback, which can be done
by simply using a managed variant to add the I2C adapter.

So add the managed functions for adding the I2C adapter.

Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Dmitry Osipenko <[email protected]>
Signed-off-by: Yicong Yang <[email protected]>
Signed-off-by: Wolfram Sang <[email protected]>