sms_vdp: Do not abort when detecting an un-implemented VDP mode
sms_vdp: Do not abort when detecting an un-implemented VDP mode

At least one game, Cosmic Spacehead, briefly passes through an unsupported
mode before settling on the mode it actually uses.

JoppyFurr/Snepulator,JoppyFurr/Snepulator,JoppyFurr/Snepulator,JoppyFurr/Snepulator,JoppyFurr/Snepulator,JoppyFurr/Snepulator