Revert "parisc: HAVE_ARCH_TRACEHOOK"

This reverts commit 81bf550d

.

HAVE_ARCH_TRACEHOOK requires defining the user_regset interfaces,
including task_user_regset_view().  parisc doesn't do that yet,
so don't lie about it.

Signed-off-by: Roland McGrath <roland@redhat.com>