drm/radeon: force MSIs on RS690 asics

commit fb6ca6d154cdcd53e7f27f8dbba513830372699b upstream.

There are so many quirks, lets just try and force
this for all RS690s.  See:
https://bugs.freedesktop.org/show_bug.cgi?id=37679

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>