Enabling gfxoff quirk results in perfectly usable
graphical user interface on HP 705G4 DM with R5 2400G.

Without the quirk, X server is completely unusable as
every few seconds there is gpu reset due to ring gfx timeout.
Signed-off-by: Peng Liu <liupeng01@kylinos.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>