[OpenCL] opencl-c.h: fix atomic_fetch_max with addrspace

Commit 3c7d2f1b ("[OpenCL] opencl-c.h: add CL 3.0 non-generic
address space atomics", 2021-07-30) added some atomic_fetch_add/sub
overloads with uintptr_t arguments twice.  Instead, they should have
been atomic_fetch_max overloads with non-generic address spaces.