drm/amdgpu: Return from switch early for EEPROM I2C address

As soon as control->i2c_address is set, return; remove the "break;" from the
switch--it is unnecessary. This mimics what happens when for some cases in the
switch, we call helper functions with "return <helper function>".

Remove final function "return true;" to indicate that the switch is final and
terminal, and that there should be no code after the switch.

Cc: Candice Li <candice.li@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Cc: Alex Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Alex Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>