drm/radeon: add quirk for MSI R7 370

Just adds the quirk for MSI R7 370 Armor 2X
Bug:
https://bugs.freedesktop.org/show_bug.cgi?id=91294



Signed-off-by: Maxim Sheviakov <mrader3940@yandex.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>