drm/radeon: add quirk for RV100 board

vbios says external TMDS while the board is actually
internal TMDS.

fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=60037

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

drivers/gpu/drm/radeon/radeon_combios.c

@@ -2470,6 +2470,14 @@ bool radeon_get_legacy_connector_info_from_bios(struct drm_device *dev)
 								   1),
 								  ATOM_DEVICE_CRT1_SUPPORT);
 				}
+				/* RV100 board with external TDMS bit mis-set.
+				 * Actually uses internal TMDS, clear the bit.
+				 */
+				if (dev->pdev->device == 0x5159 &&
+				    dev->pdev->subsystem_vendor == 0x1014 &&
+				    dev->pdev->subsystem_device == 0x029A) {
+					tmp &= ~(1 << 4);
+				}
 				if ((tmp >> 4) & 0x1) {
 					devices |= ATOM_DEVICE_DFP2_SUPPORT;
 					radeon_add_legacy_encoder(dev,