KEYS: 64-bit MIPS needs to use compat_sys_keyctl for 32-bit userspace

MIPS64 needs to use compat_sys_keyctl for 32-bit userspace rather than
calling sys_keyctl.  The latter will work in a lot of cases, thereby hiding
the issue.

Reported-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: stable@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: keyrings@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13832/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>