drm/radeon/kms: Add an MSI quirk for Dell RS690

commit 44517c44 upstream.

Interrupts only work with MSIs.
https://bugs.freedesktop.org/show_bug.cgi?id=37679



Reported-by: Dmitry Podgorny <pasis.uax@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>