powerpc: don't mess with r2 in copy_thread() and friends

kernel_thread() callbacks are *not* in modules and are not going to
be there.  And it's not even read in ppc32 ret_from_kernel_thread(),
so no need to bother with it there either.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2 files changed