net/scm: Fix typo in SCM_RIGHTS compat refactoring

net/scm: Fix typo in SCM_RIGHTS compat refactoring

When refactoring the SCM_RIGHTS code, I accidentally mis-merged my
native/compat diffs, which entirely broke using SCM_RIGHTS in compat
mode. Use the correct helper.

Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Link: https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-August/216156.html
Reported-by: "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
Link: https://lore.kernel.org/lkml/1596812929.lz7fuo8r2w.none@localhost/
Suggested-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Fixes: c0029de50982 ("net/scm: Regularize compat handling of scm_detach_fds()")
Tested-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Kees Cook <keescook@chromium.org>