iio: accel: bma220: move set_wdt() out of bma220_core

iio: accel: bma220: move set_wdt() out of bma220_core

Move bma220_set_wdt() into bma220_i2c.c instead of using a conditional
based on i2c_verify_client() in bma220_core.c that would make core
always depend on the i2c module.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202510102117.Jqxrw1vF-lkp@intel.com/
Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>