Cr2Decoder: WB: support Canon PowerShot cameras
Cr2Decoder: WB: support Canon PowerShot cameras

This supports all those cameras listed in switch statement.

Only one (known) camera with CR2 that is not supported yet:
1) Canon PowerShot G9

darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,klauspost/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,anarsoul/rawspeed,mgehre/rawspeed,anarsoul/rawspeed,darktable-org/rawspeed,anarsoul/rawspeed,klauspost/rawspeed,LebedevRI/rawspeed,mgehre/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed