drm/amdgpu: Remove second moot switch to set EEPROM I2C address

Remove second switch since it already has its own function and case in the
first switch. This also avoids requalifying the EEPROM I2C address for VEGA20,
SIENNA CICHLID, and ALDEBARAN, as those have been set by the first switch and
shouldn't match SMU v13.0.x.

Cc: Candice Li <candice.li@amd.com>
Cc: Kent Russell <kent.russell@amd.com>
Cc: Alex Deucher <Alexander.Deucher@amd.com>
Fixes: 15822529 ("drm/amdgpu: Add EEPROM I2C address for smu v13_0_0")
Fixes: c9bdc6c3 ("drm/amdgpu: Add EEPROM I2C address support for ip discovery")
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Alex Deucher <Alexander.Deucher@amd.com>