Use %zu instead of %ld when formatting size_t (#101412)
This fixes compiling on systems where `size_t` is an `unsigned int` instead of an `unsigned long int` (32 bit Raspberry Pi OS is one example).
`%ld` expects an `unsigned long int`, while `%zu` specifies that it's an unsigned size_t.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/101412
Approved by: https://github.com/albanD
