avoid underflow uint64 Point/Rect counts
avoid underflow uint64 Point/Rect counts

DNG's OpcodeFixBadPixelsList has already been converted to uint64
for Point and Rect counts to avoid integer overflows. Avoid another
overflow potential by reading the counts as unsigned.

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