drm/radeon: add a quirk for a XFX R9 270X

BugLink: http://bugs.launchpad.net/bugs/1578798

commit bcb31eba upstream.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=76490Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/gpu/drm/radeon/si_dpm.c

@@ -2931,6 +2931,7 @@ static struct si_dpm_quirk si_dpm_quirk_list[] = {
 	{ PCI_VENDOR_ID_ATI, 0x6811, 0x1462, 0x2015, 0, 120000 },
 	{ PCI_VENDOR_ID_ATI, 0x6811, 0x1043, 0x2015, 0, 120000 },
 	{ PCI_VENDOR_ID_ATI, 0x6811, 0x148c, 0x2015, 0, 120000 },
+	{ PCI_VENDOR_ID_ATI, 0x6810, 0x1682, 0x9275, 0, 120000 },
 	{ 0, 0, 0, 0 },
 };