[polly] Fix build

This produced a compile error with GCC:

llvm-project/polly/lib/Transform/ScheduleOptimizer.cpp:1220:49: error: cannot convert ‘bool’ to ‘llvm::TargetTransformInfo::RegisterKind’
 1220 |     RegisterBitwidth = TTI->getRegisterBitWidth(true);

GitOrigin-RevId: 7d91d81c6b6a456ca2362b691485c8e1b42809dd
1 file changed