drm/radeon: add a dpm quirk for Sapphire Radeon R9 270X 2GB GDDR5

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=76490

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
1 file changed