parisc: Handle kgdb breakpoints only in kernel context

commit 6888ff04 upstream.

The kernel kgdb break instructions should only be handled when running
in kernel context.

Cc: <stable@vger.kernel.org> # v5.4+
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>