runtime: use correct types in __go_ptrace shim

runtime: use correct types in __go_ptrace shim

Make the types of the addr and data arguments in the __go_ptrace shim
match the types declared in Go and the types declared by the C ptrace
function, i.e., void*. This avoids a warning about an implicit
int-to-pointer cast on some platforms.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/262340