Similar to #97796, fix the type of the `native_thread` parameter for the
arm, mips64 and powerpc variants of `NativeRegisterContextFreeBSD_*`.
Otherwise, this leads to compile errors similar to:
```
lldb/source/Plugins/Process/FreeBSD/NativeRegisterContextFreeBSD_powerpc.cpp:85:39: error: out-of-line definition of 'NativeRegisterContextFreeBSD_powerpc' does not match any declaration in 'lldb_private::process_freebsd::NativeRegisterContextFreeBSD_powerpc'
85 | NativeRegisterContextFreeBSD_powerpc::NativeRegisterContextFreeBSD_powerpc(
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
7088a5ed88