drm/amdgpu: Fix amdgpu_ras_eeprom_init()

No need to account for the 2 bytes of EEPROM
address--this is now well abstracted away by
the fixes the the lower layers.

Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>