commit
ed39fadd6df01095378e499fac3674883f16b853 upstream.
Some chips seem to need a little delay after blacking out
the MC before the requests actually stop.
May fix:
https://bugs.freedesktop.org/show_bug.cgi?id=56139
https://bugs.freedesktop.org/show_bug.cgi?id=57567
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>