If feature-level < 1 (i.e., older code), then accept all/any 4:2:0 chroma
modes, not just 4:2:0-JPEG.
(The default with no 'C' tag is still 4:2:0-JPEG, though.)
Authored by: mdoggydog 2004-04-07
Parent: [r2302]
Child: [r2304]
