drm/radeon: add additional pci revision to dpm workaround

BugLink: http://bugs.launchpad.net/bugs/1655041

commit 8729675c upstream.

New variant.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/gpu/drm/radeon/si_dpm.c

@@ -3026,6 +3026,7 @@ static void si_apply_state_adjust_rules(struct radeon_device *rdev,
 		    (rdev->pdev->revision == 0x80) ||
 		    (rdev->pdev->revision == 0x81) ||
 		    (rdev->pdev->revision == 0x83) ||
+		    (rdev->pdev->revision == 0x87) ||
 		    (rdev->pdev->device == 0x6604) ||
 		    (rdev->pdev->device == 0x6605)) {
 			max_sclk = 75000;