[ObjectFifoStatefulTransform] Reuse mlir::loopUnrollByFactor instead of custom function

[jtuyls]

I encountered an error with a reinterpret_cast operation inside aie.core, operating on an aie.objectfifo.subview.access operation. The cloned reinterpret cast would be invalid after the unrollForLoops method was called. I debugged this a bit and it seemed operands were set incorrectly in some cases, however, instead of fixing the existing method I replaced it with the upstream mlir::loopUnrollByFactor method as it would be better to reuse that one instead I think. With this change the reinterpret_cast error got resolved as well.

[AndraBisca]

I think I meant to use this at some point during the original design of the object FIFO but couldn't figure out how to do it then. I'm happy to replace the custom unrolling if it works with all of our designs! Thank you!