drm/amd/pm: Use devm_i2c_add_adapter() in the Navi10 smu

drm/amd/pm: Use devm_i2c_add_adapter() in the Navi10 smu

The I2C init for Navi10 uses i2c_add_adapter() and i2c_del_adapter(),
this commit replaces the use of these two functions with
devm_i2c_add_adapter(). Notice that Navi10 init initializes multiple I2C
buses in a loop; if something goes wrong, the previous adapters are
removed, and the amdgpu load is interrupted. Since I2C init is required
for the correct load of amdgpu, it is safe to rely on
devm_i2c_add_adapter() to handle any previously initialized I2C adapter.

Signed-off-by: Rodrigo Siqueira <siqueira@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>