i2c: core: simplify devm_i2c_new_dummy_device()

Use devm_add_action_or_reset() instead of devres_alloc() and
devres_add(), which works the same. This will simplify the
code. There is no functional change.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>