drm/amdkfd: replace asic_family with asic_type

asic_family was a duplicate of asic_type, both of type amd_asic_type.
Replace all instances of device_info->asic_family with adev->asic_type
and remove asic_family from device_info.

Signed-off-by: Graham Sider <Graham.Sider@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>