Allow overrides on the command line.

v2: agd: sqaush in spelling fix and bogus default value warning
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NRoger He <Hongbo.He@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>