drm/amd/display: fix bw_calc_auto translation error

The compiler was warning about conditions that will never evaluate
to true. The problem was that the VBA translater didn't translate
the conditions correctly.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>